#precalculus

1 messages · Page 296 of 1

sick steppe
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what's a convergent in this context...?

mystic cloak
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Its talking about Sequence

willow bear
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i'm like 3 hours late but that's literally the least helpful reply possible @mystic cloak

patent patio
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where u find this exercises?

sharp lagoon
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o-o

sick steppe
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it's a standard question to get.. idk why they asked where it was from holothink

cerulean salmon
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How can p/q be a sequence? Am I missing something?

viscid thistle
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It's probably two sequences p_n and q_n that aren't shown

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Although that would make the second part a bit nonsensical

past meadow
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maybe talking about the sequence of cut-offs of the infinite fraction of sqrt(D)? https://en.wikipedia.org/wiki/Continued_fraction#Infinite_continued_fractions_and_convergents

In mathematics, a continued fraction is an expression obtained through an iterative process of representing a number as the sum of its integer part and the reciprocal of another number, then writing this other number as the sum of its integer part and another reciprocal, and so on. In a finite continued fraction (or terminated continued fraction...

somber sigil
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In case ur still wondering after 4 days... to find the area of a circle u need to complete the square... in the form (a±b)²=a²±2ab+b², in this case b=2 for x and b=1 for y.

olive pollen
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Hi geeks, I am a homeschooler who is currently aspiring to learn Maths and Physics and I know arithmetic, Basic Algebra and Basic Geometry. So I was wondering if I should start directly with a Precalculus text or study Algebra, Geometry and Trig in detail. My main aim is to get on to calculus so that I can understand Physics

Thank You

sick steppe
fleet yew
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Precalc texts will cover basic trig

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Unit circle and the definition of the sinus and cosinus

olive pollen
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and 3blue1brown is there for rescue as always

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so I guess I should start with Precalc text

patent patio
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guys

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which book or course of precalculus is good? i think in learn in Openstax, but maybe have a better options

jagged sun
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cricket noises

steel venture
# patent patio which book or course of precalculus is good? i think in learn in Openstax, but m...

this should be a good starting point https://www.youtube.com/watch?v=eI4an8aSsgw

Learn Precalculus in this full college course. These concepts are often used in programming.

This course was created by Dr. Linda Green, a lecturer at the University of North Carolina at Chapel Hill. Check out her YouTube channel: https://www.youtube.com/channel/UCkyLJh6hQS1TlhUZxOMjTFw

⭐️ Lecture Notes ⭐️
🔗 Part 1 - Functions: http://lindagr...

▶ Play video
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it should be a good foundation for calc 1 if you practice and do mock exams along with the course

wary mulch
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idk how to approach this sum.can anyone help me

peak sandal
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You can evaluate it directly

wary mulch
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no 0*infinity form

steel venture
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👀

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ok had to make sure ann wasn't watching

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have you tried l'hopital

wary mulch
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no

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i forgot abt tat

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@steel venture

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is this crct?

steel venture
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nope

wary mulch
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wat error did i do

steel venture
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to use lhop you need 0/0 or infinity/infinity

wary mulch
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ohhh ok

mild kestrel
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So I need to find the range of this and give it in interval notation... Having said that, I'm not sure if the answer in interval notation would be this (-4, inf) or [4, inf), since I was only given the graph and no equation

nocturne jacinth
mild kestrel
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The lowest and highest y points of the slope

nocturne jacinth
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what would f(2) be?

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f(1)*

mild kestrel
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I believe (1,-4)

nocturne jacinth
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correct which shows that -4 is a possible value of the function

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do u see any y value lower?

mild kestrel
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No, so then answer should be [-4, inf)

nocturne jacinth
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u can also look at it like this, what function does this look like?

mild kestrel
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f(x)=(x^2-1)-4

nocturne jacinth
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and x^2 is centered at (0,0)

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u can plug in 0 and still get 0 and the range of x^2=[0,inf)

alpine hedge
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@wary mulch Just rewrite tan(x) in terms of sin(x)/cos(x) then use the product rule for limits s.t you get log(sin(x)/ cos(x) and can use l'Hopital as the expression is of the form 0/0.

nocturne jacinth
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this graph looks like f(x)=(x-1)^(2)-4

mild kestrel
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Got it, thank you!

copper vigil
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() means exclusion

gusty relic
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how can I graph a fast sketch of a fucntion like f(x) = 2/(3x-1)

steel venture
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desmos

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unless you mean by hand

gusty relic
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yes I mean by hand

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and without calculating it point per point if possible, just a general idea of what the function looks like

steel venture
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function transformations

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this is just 1/x, with various transformations applied to it

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you can rewrite this as $f(x)=\frac{2}{3}\cdot\frac{1}{x-\frac{1}{3}}$

obsidian monolithBOT
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maximo

steel venture
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so you're scaling it by a factor of 2/3, and shifting it 1/3 units to the right

gusty relic
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by scaling you mean it goes up by 2/3 units?

steel venture
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no, literal scaling

wet surge
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WSP PPL

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i need help.

steel venture
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what do you need help with?

wet surge
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the directions are making me confuse.

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how do i solve?

steel venture
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do you know what a sequence is?

wet surge
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direction says "for each prob. write the first-four term"

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yea

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i know how to solve etc etc. but the directions are making me confuse.

steel venture
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i'm assuming they want you to write the first four terms of each sequence

wet surge
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okay how.

steel venture
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i know how to solve etc etc

devout trail
wet surge
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and nth term for 10th term is 10. and 15th term is 15.

steel venture
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hm?

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do you know how to solve these or not

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let's start with that

wet surge
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slight yes. definetly not.

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cannot*

steel venture
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alright so let's say no

wet surge
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i have a book right here. but the book confuse me also. i need help with the person

steel venture
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i'll give you an example problem

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and an example solution

wet surge
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so i assume replacing the n of 10 or 15?

steel venture
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no

wet surge
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but the nth term is 10 and 15.

steel venture
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$a_n$ is the nth term in the sequence a

obsidian monolithBOT
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maximo

steel venture
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no

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let me ask again

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do you know what a sequence is?

wet surge
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slight.

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honest answer. slight.

steel venture
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what's your native language?

wet surge
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sequence have a consecutive terms having a commong diff?

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filipino.

steel venture
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ang pagkakasunud-sunod ay isang order na listahan ng mga numero na sumusunod sa isang karaniwang panuntunan

wet surge
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im guessing you used a translator?

steel venture
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yes

wet surge
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it doesnt translate better.

steel venture
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"a sequence is an ordered list of numbers that follow a common rule"
"ang pagkakasunud-sunod ay isang order na listahan ng mga numero na sumusunod sa isang karaniwang panuntunan"

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from either of these

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do you understand what a sequence is?

wet surge
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yes. the sequence is ordered by the list of common that follows the common difference?

steel venture
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not a common difference necessarily

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just a common rule

wet surge
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term is following the common diff, solving for the next upcoming terms?

steel venture
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no common difference

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i'll give you an example

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$a_n = n$

obsidian monolithBOT
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maximo

steel venture
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this is a sequence $a$, the nth term is $a_n$, which means the 1st term is $a_1$ the 2nd is $a_2$...

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and so on

obsidian monolithBOT
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maximo

steel venture
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so for the case of n=1, the 1st term, we have $a_n = n \rightarrow a_1=1$

obsidian monolithBOT
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maximo

steel venture
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does that make sense?

wet surge
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yea i know nth term is based on a1 or opposite

steel venture
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so what's the 20th term of this sequence?

wet surge
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lemme see it.

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actually let me try to solve it.

steel venture
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$a_n = n$, what's the 20th term?

obsidian monolithBOT
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maximo

wet surge
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okay brb

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wait no

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the problem is incomplete tho

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wait the nth is 1right?

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@steel venture

steel venture
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the nth term is n

wet surge
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yea

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and whats the value on n?

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give me problem with numbers on n.

steel venture
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what's the 20th term

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what do you think the value of n is?

wet surge
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oh

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oof

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my bad

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so sorry.

steel venture
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no need to be sorry

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so:

wet surge
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wait can we do like a real problem on arithmetic like theres an common diff

steel venture
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these problems don't have a "common difference"

wet surge
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oki.

steel venture
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so one more time, if we have $a_n = n$, and $a_1=1$ is the first term, what's the 20th term?

wet surge
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okay so whats the formula. is it an=n or an=(n-1)

obsidian monolithBOT
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maximo

wet surge
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oh

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okay

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wait

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lmao

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im really so sorry

steel venture
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no need to be sorry

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what's the 20th term?

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let me know when you have an answer, it doesn't matter if its right or wrong

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i just want to see where your head is at

wet surge
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okay back

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im confused at the formila

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formula*

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not sure if this is correct or not.

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im sorry if its wrong.

steel venture
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why are you using common difference again

wet surge
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atleast i tried tho

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wdym

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i alr remove the d on my formula

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is it allowed?

steel venture
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that's one way to do it i guess

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but it's much simpler

wet surge
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okay. show me the real answer

steel venture
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the nth term is equal to n

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so the 3rd term is equal to 3

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and the 15th term is equal to 15

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and so on

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do you see what im saying?

wet surge
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yea

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and theres a gap on your given term

steel venture
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wdym?

wet surge
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nvm

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go on

steel venture
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ok so in the sequence $a_n = n$, what's the 50th term?

obsidian monolithBOT
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maximo

steel venture
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assuming the first term is 1

wet surge
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hm

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wait

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whats the answer on the previous problem

steel venture
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you got it right, it was 20

wet surge
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50?

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49?

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is around 49-50

steel venture
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it is 50

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for the nth term in a sequence, you just need to plug in the n value into the formula

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so for example

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$a_n = n$ for the nth term

obsidian monolithBOT
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maximo

steel venture
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the 50th term is the term where $n=50$ so $a_{50} = 50$

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do you see what i did?

obsidian monolithBOT
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maximo

wet surge
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yea

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okay

steel venture
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so if i ask for the 100th term, what is the value of n?

wet surge
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100

steel venture
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ok good

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now lets do a more difficult one

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$a_n = n^2$

obsidian monolithBOT
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maximo

steel venture
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what's the 1st term?

wet surge
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1?

steel venture
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yup

wet surge
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its up to you

steel venture
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no

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its not up to us

wet surge
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okay

steel venture
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it's based on the formula

wet surge
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okay

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so give me another prob

steel venture
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so what would the 2nd term be in that sequence?

wet surge
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get another value term?

steel venture
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remember

wet surge
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oof

steel venture
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$a_n = n^2$

wet surge
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uh

obsidian monolithBOT
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maximo

wet surge
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2?

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cause there id already a 1

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therefore there qould be 2

steel venture
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we're looking for the 2nd term

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what is the value of n then? (if we're looking for the nth term

wet surge
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oof sorry having problems in wifi

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5?

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wait sorry,can we continue this later. i gotta eat.

steel venture
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sure

wet surge
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OKAY BACK

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so

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whats the second term?

steel venture
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4

wet surge
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why

steel venture
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because the 2nd term is the nth term when n = 2

sick steppe
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2^2=4...

steel venture
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and our nth term is defined as n^2

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hence n^2 for n=2, 2^2 =4

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do you get that?

wet surge
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mhm

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so 4^2

steel venture
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what is that?

wet surge
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nvm

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ok got it

steel venture
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so, what's the 5th term of the sequence $a_n = n^2$?

obsidian monolithBOT
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maximo

wet surge
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a15=n2
a15=15^2
15th term = 225

steel venture
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why did you do the 15th term

wet surge
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OOF

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I FORGOT ITS 5

steel venture
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so what's the 5th term

wet surge
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a5=n2
a5=5^2
5th term = 25

steel venture
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alright

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25 is right

wet surge
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is it correct??

steel venture
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i think you're starting to get it

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so now if i give you

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$a_n = \frac{1}{n}$

obsidian monolithBOT
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maximo

steel venture
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what are the first 3 terms?

wet surge
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wait brb

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gotta do dishes

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sorry

steel venture
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np

wet surge
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OKAY BACK

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LETS CONTINUE

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yea i got it

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give me a problem

steel venture
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$a_n = \frac{1}{n}$

obsidian monolithBOT
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maximo

steel venture
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what are the first 3 terms?

wet surge
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1,2,3?

steel venture
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no

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look at the sequence

wet surge
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i see one nth term and another nth term but half with 1

steel venture
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what?

wet surge
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what

steel venture
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let's go back to the other sequence

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$a_n = n^2$

obsidian monolithBOT
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maximo

steel venture
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what are the first 3 terms here

wet surge
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OH

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1,4,8

steel venture
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no

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1 and 4 are correct

wet surge
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10?

steel venture
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how did you get 1 and 4?

wet surge
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cause you said earlier

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wait no

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2^2=4

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and the 1 is the main nth term value

steel venture
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the 1 is the 1st term, because 1^2 = 1

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the 2nd term is 4, like you said, because 2^2=4, like you wrote

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now what would be the 3rd term?

wet surge
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if 2^2 is 4. the 2^4 is 8?

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wait no

steel venture
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remember how you found the 5th term?

wet surge
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32?

steel venture
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and the 15th term?

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this is the same thing

wet surge
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OH 15TH TERM?

steel venture
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i want the 3rd term

wet surge
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wait no

steel venture
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but you find it the same way you found the 15th term

wet surge
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1,4,3?

steel venture
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remember, the sequence goes 1^2, 2^2, 3^2, 4^2, ... n^2

viscid thistle
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What's $3^2$

obsidian monolithBOT
wet surge
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oh got it

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wait no.

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can you just tell me whats the third term

viscid thistle
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Answer my question

wet surge
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18

viscid thistle
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That's wrong, but how did you arrive at 18?

wet surge
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...

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okay you know what

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im just gonna have to fail my math this sem

steel venture
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how did you arrive at 18?

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how did you get that 3^2=18?

viscid thistle
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Depending on the contents of your math class, not knowing how to square numbers is not the end of the world

versed arrow
steel venture
versed arrow
sharp lagoon
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what can i do about the square root when it is subtraction

trim hemlock
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nothing, you just subtract it like normally how you would subtract two functions

sharp lagoon
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is (f o g)(x) which is also f(g(x))the same as (fg)

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nvm it isnt

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or iss ittt

stuck lark
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@sharp lagoon depends what you mean by fg

sharp lagoon
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(fg)(x) srry i wasnt clear

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would that just be multiplying both functions

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and (f o g)(x) is like f(g(x))

stuck lark
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i ask what YOU mean by fg

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some books mean composition, others mean product

willow bear
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why is the answer to (f+g)(x) highlighted in green despite being wrong? thonk

sharp lagoon
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EMM composition? am not sue

patent patio
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guys

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anyone know the Prof Leonard precalculus class? where i can find the exercises to practice function, trigonometry and all?

uncut mulch
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you can get some from khan, or use a generic math textbook

gusty relic
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is there a direct way to check if a function is bijective other than check for inyective+surjective?

uncut hollow
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you can sometimes just give an explicit inverse

bleak relic
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how can I solve that?

night wyvern
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Does anyone know where I can find the curriculum for Pre-Calc honors? I wanna see if I got the basics down

thorny geyser
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uhh probably ka precalc?

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some pcalc h classes have like an introduction to limits or something similar in addition to whats in KA pcalc

night wyvern
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Khan Academy?

patent patio
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if i did the check of James Stewart, i'm ready to start learn calculus 1? or will gonna be much difficult?

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i need learn more something first? or i can keep going? what u suggest?

steel venture
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did you read the entire thing?

sharp lagoon
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How can I get rid of the 1/3

viscid thistle
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Take the log

trim hemlock
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theres no need for taking logarithms

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just isolate the x^(1/3) and raise both sides to the power of 3

sharp lagoon
viscid thistle
viscid thistle
trim hemlock
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just wanted some clarification.
Translation: Given f(x) as such. Assume F is the antiderivative of f on R satisfying F(0)=2. The value of F(-1) + 2F(2) equals?
So what im confused about is are they making us assume that the antiderivative of the upper branch of the function also satisfies F(0)=2? But wouldnt the antiderivative of the upper branch of f(x) have the domain of x>=1?

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basically, what im saying is that the antiderivative for 2x+5 is undefined for x=0 isnt it?

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or am i missing something

fleet yew
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Is F meant to be continuous

trim hemlock
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its not listed in the question

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so i cant confirm

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the phrase "is antiderivative of f on R" kind of throws me off

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but then again plugging x=0 into the antiderivative of the upper branch of f(x) seems kinda illogical to me. However, this is from a past national exam paper, so they must have been checked through very thoroughly, i.e its very unlikely a mistake can be found here.

fleet yew
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Typically in this type of problem they should give you integration bounds

trim hemlock
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i suppose so too

stuck lark
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thinking of 'branches' that way isn't sensical

trim hemlock
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oh, i didnt quite know how i would say/call it

stuck lark
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"is antiderivative of f on R"
all this means is F'=f

trim hemlock
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like the portion of f(x) where it is defined as 2x + 5

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hmmm

stuck lark
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how to approach this without getting tripped up by the piecewise def of f is to think of how best to explicitly define F

trim hemlock
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should i define it as a piecewise function also?

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i mean, it must be right?

stuck lark
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for all $x\in\bR$ we have $F(x)-F(0)=\int_0^xf$

obsidian monolithBOT
#

Cryptic Dance of the Fireflies

stuck lark
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if x<1 then the rhs is easy to compute

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if x>=1 then not so easy

trim hemlock
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hmmm interesting

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never looked at it that way

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oh so basically we just have to split the integral into two different bounds?

stuck lark
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but we can be clever if $x\ge1$ and write
$$F(x)-F(0)=\int_0^xf=\int_0^1f+\int_1^xf$$

trim hemlock
#

right

obsidian monolithBOT
#

Cryptic Dance of the Fireflies

trim hemlock
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alright, thats something new for me

stuck lark
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now both integrals on the rhs are easy to compute

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so F is best explicitly defined piecewise as such

trim hemlock
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wait for the integral from 0 to 1, with the upper bound, shall i take the left hand side limit of x tending to 1?

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since that 1 is not in the domain of 3x^2+4 right?

fleet yew
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The problem occurs when you let x=0 because F(0)=2

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And the integral from a to a is necessarily 0

trim hemlock
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strange

stuck lark
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an alternative version of ftc lets us swap evaluations of F by limits of F

trim hemlock
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erm theres a website that has quite a different approach but comes up with the same results as yours

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so many ways that we could define antiderivative of piecewise functions

stuck lark
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by this alternative version, $\lim_{x\to1^-}F(x)$ exists and
$$\int_0^1f=\lim_{x\to1^-}F(x)-F(0)$$

obsidian monolithBOT
#

Cryptic Dance of the Fireflies

trim hemlock
#

right

stuck lark
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this ensures we need not worry over computing int[0,1]f (even without this alternate version of ftc, one can intuit this is how the computation 'should' work out anyway)

trim hemlock
#

alright

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thank you very much for these information

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this question is interesting

stuck lark
#

you're welcome ThumbsUp

hollow flint
#

by any chance could somone pin the half angle formulas

hollow flint
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k

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do i have to memorize the sum to product and visa versa for a pre calc test?

fading rapids
#

in the equation $x^x=x$, the solution is $x=1$. I've been trying to solve $cx^x=x$ for $c \in \mathbb{R}$ but I can't get very far. any ideas/tips?

obsidian monolithBOT
toxic flame
#

let me rephrase, break it into cases when c is in [0,1] and when c is not in [0,1]

fading rapids
violet vale
#

When is it a good time to define 0^0 =1 or 0^0 = undefined?

trim hemlock
#

0^0 is undefined

violet vale
#

I think its depends on context?

trim hemlock
#

well idk, that seems like a discussion-wise topic

violet vale
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Should I even need to worry about this for use in calculus?

trim hemlock
#

but 0^0 is undefined on its on

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however x^x converges to 1 as x goes to 0+

violet vale
#

I agree with that limit

patent beacon
copper swallow
#

<@&268886789983436800>

viscid thistle
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@fading rapids do you still need help?

torn parcel
#

hello can someone pls explain to me why the graph of the semi circle in this case is |x|≤2 and not |x|≥2

strong marlin
#

So you want to display the semi circle when x <= 2 and x >= -2

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which is the same as saying |x|<= 2

torn parcel
#

OHHH I SEE

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idk why i wasnt able to grasp it while our teacher was explaining tysm

strong marlin
#

np

viscid thistle
#

I'm having a hard time understanding this

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Why is this a thing that you can do?

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Wait nevermind I got it

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Feelsgoodman

gusty relic
#

any hint on how to approach this limit?

toxic flame
#

hmm. @gusty relic
\begin{align*}\left(\sqrt{x+\sqrt{x}}+\sqrt{x-\sqrt{x}}\right)^2&=x+\sqrt{x}-2\sqrt{(x+\sqrt{x})(x-\sqrt{x})}+x-\sqrt{x}\&=2(x-\sqrt{x^2-x})\end{align*} and
$$(x-\sqrt{x^2-x})=(x-\sqrt{x^2-x})\frac{x+\sqrt{x^2-x}}{x+\sqrt{x^2-x}}=\frac{x}{x+\sqrt{x^2-x}}=\frac{1}{1+\sqrt{1-\frac{1}{x}}}$$

obsidian monolithBOT
#

c squared

toxic flame
#

so your original limit approaches ||1||

#

i suppose alternatively you could do
\begin{align*}
\left(\sqrt{x+\sqrt{x}}-\sqrt{x-\sqrt{x}}\right)&=\left(\sqrt{x+\sqrt{x}}-\sqrt{x-\sqrt{x}}\right)\frac{\left(\sqrt{x+\sqrt{x}}+\sqrt{x-\sqrt{x}}\right)}{\left(\sqrt{x+\sqrt{x}}+\sqrt{x-\sqrt{x}}\right)}\&=
\frac{x+\sqrt{x}-x+\sqrt{x}}{\left(\sqrt{x+\sqrt{x}}+\sqrt{x-\sqrt{x}}\right)}\
&=\frac{2\sqrt{x}}{\left(\sqrt{x+\sqrt{x}}+\sqrt{x-\sqrt{x}}\right)}\&=
\frac{2}{\left(\sqrt{1+\frac{1}{\sqrt{x}}}+\sqrt{1-\frac{1}{\sqrt{x}}}\right)}
\end{align*}
and see what happens as $x\to\infty$

quick bluff
#

Rationalizing and dividing both numerator and denominator by sqrt(x) might be simpler

obsidian monolithBOT
#

c squared

quick bluff
#

Ye

obsidian monolithBOT
#

T0lgi01

shut totem
#

I think you can do it a bit easier:
$$\lim_{x \to \infty}\sqrt{x+\sqrt{x}}-\sqrt{x-\sqrt{x}} =$$ $$ \lim_{x \to \infty}\sqrt{x^2+x}-\sqrt{x^2-x} = \lim_{x \to \infty}(x+ 1/2) - (x- 1/2) = 1$$
The first equation is a substitution $x \mapsto x^2$, the second one is the general formula
$$\lim_{x \to \infty} \sqrt{x^2+ax} -x = a/2$$
You can prove this by turning this into a fraction and multiply numerator and denominator by the conjugate

obsidian monolithBOT
#

T0lgi01

shut totem
#

Ah I should still append the proof
$$\lim_{x \to \infty} \sqrt{x^2+ax} -x = \lim_{x \to \infty}\frac{(\sqrt{x^2+ax} -x)(\sqrt{x^2+ax} +x)}{\sqrt{x^2+ax} +x} $$ $$= \lim_{x \to \infty}\frac{ax}{\sqrt{x^2+ax} +x} = \lim_{x \to \infty}\frac{a}{\sqrt{1+a/x} +1} = a/2$$

obsidian monolithBOT
#

T0lgi01

fading rapids
bleak relic
obsidian monolithBOT
#

leonardomoura

$c=\frac{x}{x^x}\Rightarrow{c=({\frac{x}{x})}^{1-x}}\Rightarrow{c=1^{1-x}$ if $x=1$ then $c=0$
```Compilation error:```! Missing } inserted.
<inserted text> 
                }
l.55 ...\frac{x}{x})}^{1-x}}\Rightarrow{c=1^{1-x}$
                                                   if $x=1$ then $c=0$
I've inserted something that you may have forgotten.
(See the <inserted text> above.)
With luck, this will get me unwedged. But if you
really didn't forget anything, try typing `2' now; then
my insertion and my current dilemma will both disappear.```
fading rapids
#

@bleak relic I don't think you can go from x/x^x to (x/x)^(1-x)

shut totem
#

by that you would get x^{1-x}

bleak relic
#

i made an error

obsidian monolithBOT
#

leonardomoura

bleak relic
#

which is $1^{b-c}$

obsidian monolithBOT
#

leonardomoura

fading rapids
shut totem
#

So I don't think this has any analytical solution like $x^x = x$. When I write the equation like
$$x^x = cx \Leftrightarrow e^{x\ln x}-cx = 0,$$
this doesn't seem solvable in general. I know that $e^x -x = c$ in general is like this, too.

obsidian monolithBOT
#

T0lgi01

shut totem
#

but I'm pretty sure you can approximate this very quickly somehow I feel like

strong marlin
#

You said you solved x^x = x?

#

surely cx^x = x -> cx(x^x-1 -1)=0, thus c=0,x=0, x^x = x ?

steel venture
#

x^x = x
x^(x-1) = 1

shut totem
#

I think c=1 is the only c for which this is easy

steel venture
#

as long as x does not equal 0

ornate island
#

im stuck on finding the coordinates of each side of this inscribed rectangle

#

i know the zeros are 6 / -6

#

but idk how to find the actual coordinates of x

ornate island
#

can someone ehlp

steel venture
#

i don't get your question

#

which part are you on?

ornate island
#

im trying to figure out the length of the sides of the rectangle

#

by trying to find out what coordinate the corners are on

steel venture
#

which part are you on?

ornate island
#

part a

#

lol

steel venture
#

look at how the 4 coordinates are shown in the picture

#

those will be the 4 vertices for any value of x between -6 and 6

#

so now pay attention to the bottom side of the rectangle

#

what are the 2 vertices that form that side?

ornate island
#

wouldnt it be 0

steel venture
#

?

strong marlin
steel venture
ornate island
#

like

#

(x, 0) and (-x, 0) are the vertices

#

that form the bottom side

steel venture
#

yes

#

so what is the length from (x,0) to (-x,0)

ornate island
#

uh

steel venture
#

try using the distance formula

ornate island
#

sqrt((-x-x)^2 + 0)?

steel venture
#

not quite

#

oh wait

#

thats it yeah

#

what does that simplify to?

ornate island
#

-2x

#

?

steel venture
#

2x, but yeah

ornate island
#

oh wait i forgot

#

to square both

#

mb

#

so the distance is 2x

steel venture
#

yes

#

that's for the bottom and top sides

#

now look at either of the sides on the left and right

fading rapids
steel venture
#

and apply the same idea

ornate island
#

if the y coord is f(x)

#

we just plug the equation in for that

shut totem
#

in fact a bit lower should also work

ornate island
#

not sure what to put in for f(x) using the distance formula

strong marlin
steel venture
#

what's our function?

ornate island
#

36 - x^2

#

so we plug that in

#

?

steel venture
#

yeah

ornate island
#

ok

steel venture
#

do you understand why?

ornate island
#

yeah

shut totem
#

I thought, given c, we should find all x that satisfy cx^x = x (or x^x = cx)

steel venture
#

so for any k>0 it should have 1 solution (i think)

strong marlin
#

Plotting yx^{x}-x=0 produces something otherwise

steel venture
#

no that's not the case (to what i said)

strong marlin
#

if you plot yx^{x}-x=0 you get a range of values for y and x

ornate island
#

wait the height is just going to be 36-x^2 right @steel venture

steel venture
#

yes

ornate island
#

i plugged it in the distance formula and yeah

#

so the area of the entire rectangle is just 2x(36-x^2)

steel venture
#

exactly

ornate island
#

aight ty

shut totem
#

c = 0.01 shouldnt give any answers x>0, going for x<0 is weird because then we have complex numbers

#

,w x^x

strong marlin
#

are we saying x has to be an integer or something?

ornate island
#

how do we express the area as a function?

shut totem
#

no, just a real positive number

#

,w plot x^x

ornate island
#

is it just A(x) = 2x(36-x^2)

obsidian monolithBOT
steel venture
ornate island
#

a ok

strong marlin
shut totem
#

If we plot cx, then if we choose c small enough, they don't intersect

steel venture
#

i think you guys are talking about different graphs

strong marlin
#

Intuitively we can rewrite this as x^X = 1/c x = ax. So if a is large enough (as in x^x-1), it works. So there should be plenty of solutions

#

And like i said before, the graph has infinitely many solutions for y = 0

#

which *I do * like the idea of

#

y=0 *

#

^ actually very strange

steel venture
#

x^(x-1) = 0 only has 1 solution

strong marlin
#

Incorrect actually, its just the grapher was getting too close to 0

steel venture
#

actually i don't think it has a solution at all

strong marlin
shut totem
#

x = 1 is a solution

#

nvm I misread

steel venture
#

ln(x) = 0/(x-1), nvm you can't even do this

shut totem
#

wait ICSF could you explain what exactly you want to solve?

steel venture
#

so there's no solution to the equation

strong marlin
#

Yes there is

#

x = 2, c=0.5 for example

#

0.5 * 2 ^2 = 2

steel venture
strong marlin
#

This is just a big miscommunication :/

#

(from me)

shut totem
#

let's just say f(x) = x^x, yes? We want to find, given c, solutions to f(x) = cx (I just put c on the other side because I feel it's a bit easier)

#

if c = 1, then we have exactly one solution x=1

#

if c=2 then we have two solutions x=2 and x = 0.3463233622785809

strong marlin
shut totem
#

I dont think it does

strong marlin
#

x^x is continuous? y = tan(theta)x. And theta can get infinitely fine. We can intersect any angle between 90 and 0

shut totem
#

since the derivative of x^x after a certain point is always bigger than c, there can be at most only one intersection after that

strong marlin
#

Yes but we can find a c which equals 1/x^x-1

#

giving by definition cx^x = x

#

as x^(1-x) * x^x = x = x

shut totem
#

So you want to fix x and find possible values for c?

strong marlin
#

no

#

Im saying we can always produce a c which intersects with x^X at any point

shut totem
#

sounds trivial to me

strong marlin
#

Ah, i see what you mean

#

there is only 1 solution per value of c

shut totem
#

you can prove that for any continuous function

strong marlin
#

thats what you are saying?

shut totem
#

actually what I'm trying to say:
If c<1, there exists no x, such that x^x = cx
If c=1, there exists one x, such that x^x = cx (x=1)
If c>1, there exists two x, such that x^x = cx

#

for example c = 2 admits x = 2 (as you said) and x = 0.3463233622785809 as solutions

strong marlin
#

I see what you mean, yes

bleak relic
#

@fading rapids you got your problem solved?

fading rapids
#

not yet

#

oh actually I didn't realize people were having a conversation about my problem

#

lemme read these

bleak relic
#

ok haha

#

lemme know if you got an answer

fading rapids
shut totem
fading rapids
#

oh alright, thank you for the insight

cyan cape
viscid thistle
#

what is this? @cyan cape

#

and you might have to take a closer pic if you need help with any

cyan cape
cyan cape
ornate island
#

can someone help me clarify what it means to "State the number of nonreal complex zeros"

copper vigil
#

it means to state the number of nonreal complex zeros

#

there is no simpler way to state it

#

find the nonreal solutions to the polynomial

#

how many of them are there?

hard onyx
viscid thistle
#

Dude

#

I don't know how to describe what I'm feeling but it's the first time it was explained to me why it is like this

#

Not sure if this is the correct channel for this

stuck lark
#

not really precalc material

#

each intermediate step is justified by a field axiom or a corollary of them

patent patio
#

where i can find some exercises to practice precalculus?
i'm studyng with this course
https://www.youtube.com/watch?v=eI4an8aSsgw&t=9064s

Learn Precalculus in this full college course. These concepts are often used in programming.

This course was created by Dr. Linda Green, a lecturer at the University of North Carolina at Chapel Hill. Check out her YouTube channel: https://www.youtube.com/channel/UCkyLJh6hQS1TlhUZxOMjTFw

⭐️ Lecture Notes ⭐️
🔗 Part 1 - Functions: http://lindagr...

▶ Play video
steel venture
#

most precalculus textbooks should have problems to go along with them

#

that's one you can use

willow bear
#

@molten garnet no advertising.

molten garnet
#

oh sorry

#

is this not allowed in other servers as well?

grizzled orchid
#

Yeah don't post advertisements here

#

Or really in most servers... you should read #rules

molten garnet
#

oh

#

my bad sorry guys

dusk edge
#

Send invite bro

viscid thistle
#

no

molten garnet
#

Lol I don’t wanna get banned

#

Or removed from the server

toxic flame
#

to late

molten garnet
#

They removed my invite so no

glacial lantern
#

how do i solvew 2(x+1)(x-3)^2 - 3(x+1)^2(x-3)

trim hemlock
#

you cant

uncut mulch
#

wdym by solve?

dusky estuary
#

i presume he wants to find x

glacial lantern
glacial lantern
glacial lantern
glacial lantern
dusky estuary
#

it's already factored??

#

oh wait

#

nvm

trim hemlock
#

Instead of saying factor 4 times

#

Just say, the problem asks to factor the expression

#

Also factor does not mean solve

#

(Just saying)

#

Anyway, look for the common things both terms have

#

And then factor it out

willow bear
hollow flint
#

i just took a pre calc test

#

and 1/4 of the test was logs

#

i didnt do much logs in the text book...

#

(im just mad cause i failed the test after putting 150+ hours and wasting my summer break)

viscid thistle
#

how do i find the domain definition of this one? Ik its basic but i am not sure

uncut mulch
#

try not to overthink this

#

do you know the definition of domain?

viscid thistle
#

It's Df = - infinity to + Infinity

viscid thistle
#

That's not the definition of domain

#

But it is the right answer in this case

ornate island
#

can someone help explain this?

#

because i dont think there are any zeros

willow bear
#

there are, they're just complex.

ornate island
#

how can i factor the function knowing that 1+2i is a zero?

#

idgi

willow bear
#

do you know that for a polynomial with real coefficients, the complex zeros come in conjugate pairs?

ornate island
#

i know that they come in pairs

#

didnt know they were conjugates

#

so is (1+2i) & (1-2i) the pairs?

#

,w roots x^4-x^3-14x^2+24x+5

obsidian monolithBOT
willow bear
#

you can construct a quadratic with those as roots, and divide your polynomial by it

ornate island
#

ah ic

#

so i multiply x -1 -2i with x -1 +2i since they have to = 0 right

willow bear
#

...yes

ornate island
#

,w roots x^4-8x^3+27x^2-50x+50

obsidian monolithBOT
unique heath
#

Please help me Solving this

uncut mulch
#

what have you tried?

ornate island
#

Can someone help me with part a of this question

#

I need to find how to combine the volume of a sphere and a cylinder together

steel venture
steel venture
ornate island
#

is the height of the hemisphere also x?

steel venture
#

do you know what a hemisphere is?

vagrant ingot
#

ive tried multiple times i just dont know what to do

willow bear
#

@vagrant ingot so you don't know the defining formula for average rate of change?

#

oh, sorry, i'm 50 minutes late. do you still need help with this?

vagrant ingot
#

and school started less than a week ago

willow bear
#

so you're doing assignments ahead of the class, are you?

#

okay, so the average rate of change is simply the slope of the line connecting the two relevant points on the graph of your function

#

to put that more symbolically, the average rate of change of a function f(x) from x=a to x=b is the slope of the line connecting (a, f(a)) and (b, f(b))

#

or to put that even more formulaically to relieve you of any need for an INT skill check, it's (f(b)-f(a))/(b-a)

limpid schooner
#

$ sin^4 (x) + a sin^2 (x) + 1 = 0. $ For what value of 'a' equation has solution? How to proceed. I tried substituting t = sin^2(x) but didn't reach to any result.

willow bear
#

you will get the equation t^2 + at + 1 = 0

#

you want this equation to have a solution in [0,1]

#

do you understand why? @limpid schooner

limpid schooner
willow bear
#

the range of sin^2(x) is [0,1]

limpid schooner
willow bear
#

if t^2 + at + 1 = 0 turns out not to have solutions in that range, then the original trig equation will fail to have any solutions

limpid schooner
#

Oh.

#

So, i should satisfy these value to obtain 'a'?

willow bear
#

i don't know what you mean by 'satisfy these value'

limpid schooner
#

What to do next?

willow bear
#

well now you want the equation to have at least one solution in [0,1]

#

there's a nice shortcut way to determine what a can be

#

and it may sound a little odd, but you can do so by isolating a in the equation.

limpid schooner
#

isolating? I didn't understand the term.

willow bear
#

solve the equation for a (in terms of t)

#

make a the subject

#

whatever you call it

limpid schooner
#

Ohh. I see. I will try it

hallow nimbus
#

Hi everyone. I need help with a matter for which I can't seem to find a solution.

On Desmos, I am trying to do a cubic regression to find a cubic function of best-fit for a particular series of data points. You can see this on the left in the picture I have posted below. The regression works out well, as it displays a cubic graph that goes through 94% of the points, and the specific parameters of a,b,c, and d that go with it.

However, when I try to place these parameters into the general form of the equation y = ax^3 + bx^2 + cx + d, I actually do not get the same graph (see: the black graph is displaced quite far above the blue graph even though they both seem to take the same appearence)! I copied down the parameters correctly, so I have no clue what the problem is. A YouTube tutorial also suggests that you can simply copy the parameters and place them into the general form of the equation to get the same graph, but as you can see, the black graph (the equation) is completely different from what I get in the cubic regression in the blue graph.

Any help is appreciated. Thank you so much

glacial lantern
#

how do i solve [-x^3 (1-x^2)^-1/2 - 2x(1-x^2)^1/2)]/x^4

steel venture
#

$\frac{-x^3 \times (1-x^2)^{ - \frac{1}{2}} - 2x \times (1-x^2)^{\frac{1}{2}}}{x^4}$

steel venture
obsidian monolithBOT
#

maximo

glacial lantern
wooden reef
#

meth

trim hemlock
#

doesnt look like meth

#

wasted a police report

wooden reef
#

pls help me

fleet yew
#

@wooden reef
what can you tell me about the slopes of lines that are perpendicular and parallel to another line?

wooden reef
#

nvm I got ty

jovial stratus
#

Is this the right place where I can ask about finding domain and range?

uncut mulch
#

yes

jovial stratus
#

y = 3/x+4

#

The domain is all real numbers am i correct?

#

And x ≠ 4?

uncut mulch
#

do you mean
$$y=\frac3x + 4$$
or
$$y = \frac{3}{x+4}$$

obsidian monolithBOT
#

ℝamonov

jovial stratus
#

-4*

jovial stratus
uncut mulch
#

set of reals excluding -4, yes

jovial stratus
#

Ok, and I can't quite understand how to get the range.

#

Is it all real numbers except 0?

uncut mulch
#

yes

jovial stratus
#

Ok, thank you!

ornate island
#

,w roots x^3 - 1234567800x^2 + 1358022057x + 323703700758

obsidian monolithBOT
uncut hollow
#

ouch

ornate island
#

i typed it wrong

thorny geyser
#

since generally, finding the domain is much easier than finding the range of rational funcs

obsidian monolithBOT
#

TheToadSage

#

TheToadSage

thorny geyser
#

but you also have to make sure that you cant have a y value that obtains a $x$ value that is not in the domain of the func

obsidian monolithBOT
#

TheToadSage

thorny geyser
#

so you cant have $\frac{3-4y}{y}=-4$

obsidian monolithBOT
#

TheToadSage

thorny geyser
#

this equations has no solutions, so the only real number that is not in the range of the function is $0$

obsidian monolithBOT
#

TheToadSage

untold otter
#

hii

jovial stratus
#

Can anyone help me find the range of this equation? y=4x²+3x-1

#

Any help would be appreciated

viscid thistle
#

okay.

#

have you tried anything?

jovial stratus
#

Yeah but I cant seem to get to the answer

viscid thistle
#

can i please see it?

jovial stratus
#

I know the domain is all real numbers since it is quadratic

viscid thistle
#

yeah

jovial stratus
#

I tried the formula -b²+4ac/4a

#

And found that the limitation is -25/16

jovial stratus
toxic flame
#

-b/2a is the vertex of the parabola, which is the minimum value of f, since your function is a parabola that opens upwards

viscid thistle
#

yeah, with this we can figure out that the range will be from the minimum up to +infinity.

random root
toxic flame
#

why tho

random root
# toxic flame why tho

The square part would be zero and the remaining constant would be the minimum value I guess

ornate island
#

f(5-x) = f(-x-5)

#

can someone explain why this is the same

random root
velvet jungle
#

if f(x)=x,
then
f(5-x)=5-x=-x+5
but f(-x-5)=-x-5, which is not -x+5

jovial stratus
#

Hi i need hep in writing my answer in range

#

{y element R : y>=-25/16}

#

How can i write this in word form? like set of non-negative real numbers such that y ≥ 1

#

Wil i write set of all real numbers or set of non-negative real numbers?

steel venture
#

${y \in R : y\geq \frac{-25}{16}}$

obsidian monolithBOT
#

maximo

steel venture
#

is this what you have @jovial stratus ?

#

if so, this is saying that y belongs to the set of real numbers, where y is greater than or equal to -25/16

viscid thistle
#

Does anyone get why did we have to plug in x1=6 into equation 2 x1+3x2=12 instead of x1+4x2=24? even though B is the point of intersection between x1=6 and x1+4x2=24 and not x1+3x2=12

viscid thistle
# viscid thistle

It might have been an error, but your right, it should have been x1+4x2=24 for finding point B.

jovial stratus
wooden reef
#

how do you do this

random root
copper vigil
#

as with any upwards quadratic there will be two intervals

#

you must take their intersection

unborn nimbus
#

how do we do this question?

willow bear
#

do you know what f(2) = 1 means in terms of graphs?

#

@unborn nimbus

unborn nimbus
#

nope, i haven’t learned that

willow bear
#

you haven't learned anything about graphing functions at all?

unborn nimbus
#

ive only self studied graphing quadratic functions

willow bear
#

but surely you must know the basic principle of function graphs?

#

surely it's not just an empty ritual to you?

#

like

#

okay, let's put it this way:

#

if the graph of a function f(x) passes through the point (1, 19)... it signifies that f(1) = 19.

#

is this familiar to you?

unborn nimbus
#

ahh yeah i understand that but i was never taught lol

willow bear
#

it's really hard to believe you were never taught that.

#

not being taught that means not being taught how to read graphs.

unborn nimbus
#

i think were gonna learn it in a few weeks

willow bear
#

it's an inexcusable omission on your teacher's side, if indeed they never so much as mentioned it.

#

you're going to learn it in a few weeks?

#

then why have you been assigned this exercise?

unborn nimbus
#

i think soo, since were on composite functions rn

unborn nimbus
willow bear
#

you're on composite functions??

unborn nimbus
#

yeah

willow bear
#

then you MUST have been taught things about graphs

#

like cmon, this is the basics of the basics

unborn nimbus
#

i think we’ve only went over quadratics and thats it… i self studied the rest

willow bear
#

then your teacher's a sham, or you didn't pay attention at the critical moment.

#

in any case, ok, one way or another you have the required knowledge here.

#
if the graph of a function f(x) passes through the point (1, 19)... it signifies that f(1) = 19.
is this familiar to you?
freya — Today at 09:27
ahh yeah i understand that but i was never taught lol
#

based on this... refer back to your question, and observe that you are told f(2) = 1 and f(5) = 3.

#

this means that the graphs of your functions must all pass through two points. can you name the points?

unborn nimbus
#

(2,1) and (5,3)

willow bear
#

great.

#

so your job now is to draw any three function graphs which pass through these points.

#

as in, you should get a piece of paper, draw a set of coordinate axes, mark those two points, and then sketch three different curves going through them.

unborn nimbus
#

alrightt

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so any curve?

willow bear
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yes, so long as it passes the vertical line test

unborn nimbus
#

okay got it, thanks!!

viscid thistle
#

How do I deriviate this function? I don't really know what to do with the 7 neither do I know what to do with the 2 above the ()

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it's 7(-4x^3 + x^2 - 6x)^2

willow bear
#

,rccw

obsidian monolithBOT
viscid thistle
#

<@&268886789983436800> you should probably delete this one too

slender river
#

banned but why is it not deleting

#

hmmcat

viscid thistle
#

And check the other channels for more 😄

slender river
#

ok there we go

dry mauve
#

Evaluate

peak sandal
#

no you

ornate island
#

does anyone know how to rotate a graph 90 degrees on desmos

copper vigil
#

say you have the point (1,1)

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to rotate it by 90 degrees you turn the point into (-1,1)

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so if you have y=f(x) just turn it into f(-x)

formal walrus
#

I would probably use (0,1) as another example and that gets transformed into (-1,0) because then you know that (x,y) maps to (-y,x)

#

(in the (1,1) case, x = y = 1)

copper vigil
#

oh yeah nvm then i'm wrong

#

right because the perpendicular line is the negative reciprocal

granite meteor
steel venture
#

there's 2 main things to know about problems like these

#

each of these functions have distinct shapes which you can sort of memorize

#

as you deal with them more and more it'll become second nature what functions belong to what depictions

#

the other thing is that you can always plot a few points to see the pattern

#

take the case of y=e^(-x)

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f(0) = e^(-0) = 1

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f(1) = e^(-1) = 1/e

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f(2) = e^(-2) = 1/(e^2)

#

f(10) = e^(-10) = 1/(e^1)

#

this hints at the idea that as x becomes bigger and bigger, e^(-x) will become smaller and smaller

#

so the best graph in this case for e^(-x) will be the second graph on the right

#

you can also show that as x becomes bigger on the negative side (-1, -2, -3...)

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then e^(-x) will become larger and larger in value

ornate island
#

does anyone know if i apply the bound theorem to [-5, 5] or [-200, 1000]

#

or both

ornate island
#

,w roots 6x^4 - 11x^3 - 7x^2 +8x -34

obsidian monolithBOT
ornate island
#

,w roots x^3+x^2-8x-6

obsidian monolithBOT
cinder reef
#

Why is it that we can factor out an equation like 2(x+1)-x^2(x+1) by making it into (-x^2+2)(x+1) ?

#

I can group, I just don’t know why we can do that

viscid thistle
#

Distributivity

cinder reef
#

What do you mean by that ?

viscid thistle
#

The property that allows you to do that is distributivity

#

It is inherent to multiplication and addition

full meteor
#

If you know how distributivity works, you can see that (a + b)(c + d) = a(c + d) + b(c + d).
We are taking the equality the other way.

cinder reef
#

Alright I understand that now, thank you

cloud olive
#

How do you do this?
Find the values of θ between 0 <_ θ < π that form the portion of the graph r = 5sin (3θ) in Q4.

cloud olive
#

<@&286206848099549185>

narrow niche
#

im so lost on finding ordered pairs on the unit circle any help?

frigid wagon
#

Why can't logarithm have a negative base?

autumn plover
#

well it can

#

but the answer wont be real

shut timber
#

how can you solve one sided limits analytically?

willow bear
#

and what, pray tell, do you think the limit of f(x)g(x) should be?

#

$f(x) \lim_{x\to0} g(x) + g(x) \lim_{x \to 0} f(x)$ is not a valid answer, as the limit is a number and its value cannot depend on $x$

obsidian monolithBOT
willow bear
#

really, i think you should familiarize yourself with how the derivative product rule is defined.

#

as-is, it sounds like you see it as nothing but a symbolic rule handed down from on high

sudden patrol
#

Anyway...

#

,help

obsidian monolithBOT
#

A brief description and guide on how to use me was sent to your DMs!
Please use ,list to see a list of all my commands, and ,help cmd to get detailed help on a command!

daring wolf
#

I need help with this

#

Im new to pre calc and I'm having trouble

torn acorn
#

end behavior basically describes how the y value acts as it approaches either x=infinity or x=negative infinity

#

so you would write it in the format of X->infinity , y-> either positive or negative infinity depending on what the y value is doing

daring wolf
#

whats the y value on this

torn acorn
#

depends on which side youre looking at

daring wolf
#

Left

torn acorn
#

well, as the x value approaches the left, what number is the y value approaching @daring wolf

daring wolf
#

X -3

torn acorn
#

not quite. so, since the image goes off the graph and continues on forever, the x value is going to continue towards negative infinity. and since the y value is also going down, IT goes towards negative infinity as well. so on that side, the end behavior is, "as x approaches negative infinity, y approaches negative i infinity

#

@daring wolf

daring wolf
#

So x is -infinity

torn acorn
#

<@&286206848099549185> can one of you help me better explain this

torpid grotto
#

@daring wolf this is an example ... y=tanx , here at x=pi/2 y tends to infinity ... if you keep zooming out you will notice that the grpah near pi/2 will almost coinside and will look similar to x=pi/2 (so y is not stoping(as their is no finite value of y at x=pi/2) but x is const )

#

on the left side in ur question we can assume at a particular value of x , y will tend to - infinity

icy spruce
#

I need help with this problem f(x) = 7/1-lnx I need to find the domain in interval notation. I barely understand natural log except that it's the opposite I believe

icy spruce
#

My bad

dusk edge
#

But if you look at the graph of ln x you see it doesn’t take on the value of 0

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Meaning x>0

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Also the denominator can’t be 0

#

Meaning x can’t be e

#

Meaning 0<x<e , x>e

sick steppe
dusk edge
#

Oh ok

daring wolf
#

Alright thanks

willow bear
#

$\int x^3 \cos(x/2) \sqrt{4-x^2} \dd{x} = 0$ by symmetry, so your integral reduces to $$\int_{-2}^2 \frac12 \sqrt{4-x^2} \dd{x}$$

obsidian monolithBOT
willow bear
#

do you at least understand what i've said so far?

#

also i just realized i missed the bounds on the very first integral in my latex sorry

#

anyway here is the graph of y=sqrt(4-x^2)

#

it is a semicircle

#

the integral of an odd function over a symmetric interval is 0

#

you know what an odd function is, right?

#

this is a bit shoddy but it's the first google image search result

drowsy helm
#

can somone help me with my homework??? its about ellipse

#

determine the standard equation of an ellipse

#

nothing at all HUHUHUH

#

co vertices

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nope

drowsy helm
crimson iron
#

finding the standard equation a hyperbola with given asymptotes and one vertex

#

im stuck

#

how do i find b^2 here?

prisma hearth
#

Hi! i was wondering if anyone knew how to solve this?

viscid thistle
viscid thistle
#

For example both function has the same y intercept. Np

stuck lark
#

nani

distant valley
#

i rememeber

#

x/x^2 + c

#

it literally took me

#

30 mins to figure out LMAO

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ignore pls

stuck lark
#

f

acoustic galleon
#

I think this is true: If I have a ball and I slice the ball with two parallel planes, is it true that both hemispheres had the same volume "cut off" by the planes?

willow bear
#

no?

#

take the unit ball centered at the origin and take z=0.5 and z=-0.1 as your slicing planes

ornate grove
#

Could some one help me out

uncut hollow
#

what is [[x]] here, floor?

#

try going through conditions one by one e.g. checking f(sqrt(5)) for all of them to narrow down possibilities

digital cloud
worldly badger
# ornate grove Could some one help me out

So you can just test each function with x = sqrt(5).

  1. f(sqrt(5)) = 5 so it doesn’t t match
  2. f(sqrt(5)) = sqrt(5) so it doesn’t match too
  3. f(sqrt(5)) = 5 - 3 = 2, it match + it s define in R (ez to prove if you need to do that) + but the range isnt Z because the range of x^2 is R, etc… (I let you end the demonstration). So it doesn’t work
  4. f(sqrt(5)) = [[2.2… ]] = 2 match + domain is R + here the range is Z (we only have integer by taking the floor)
spice wave
#

can i get help

#

with 7 questiosn

night cave
#

Why is there no close bracket

dapper hollow
#

its a piece-wise function

#

thats just the way they are written

night cave
#

There has to be a reason

viscid thistle
#

its just notation thats all

#

you might be able to look up the history of piecewise functions to find out

uncut mulch
#

though there should be a separator like a ; , , , if, for

digital cloud
#

it represents it sorta being split up

#

into 2 different functions depending on what x is

naive moss
#

hi could i get some help on understanding this question? am a bit stuck with the absolutes. I tried to fit in x = -1 and x = 1 but am getting that f(x) = 1 in both cases

willow bear
#

no shit