#precalculus

1 messages · Page 86 of 1

polar phoenix
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the only numbers im given is t5 and t8 its asking me to solve for the common difference and find t1 but i think my solution is wrong

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so common diff =3

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yeah ts is def wrong, i just dont know where to start this off

rough leaf
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yeah so if common diff is 3

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and as the t values increase the numbers increase

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if you wanna go down

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js subtract 3

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like t4 wpuld be like 13

round geyser
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What’s this about

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Is it arithmetic sequence

rough leaf
round geyser
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You notice

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They’re inverses

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And it can relate addition to multiplication

polar phoenix
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wait so i am right but wth

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the solution my teacher used looked so complicated

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can someone tell me if my way of doing it is correct or was i lucky? i still cant understand how she solved it compared to the way i did it

unreal plover
#

can someone explain why at 0.5 where the red graph's slope is 0 the blue graph (red's derivative) isn't 0

placid fiber
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,w d(sqrt(3-x)+sqrt(2+x))/dx at x=0.5

obsidian monolithBOT
unreal plover
long ruin
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How much math i need to know to start studying precalculus

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Algebra 2 and geometry/trigonometry is enough??

karmic brook
viscid thistle
round geyser
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What’s Type I, II, and III about

fervent elk
raw hill
#

<@&268886789983436800>

torpid rain
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I think I know what logs are

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Doesn't it have to do with stuff like 10^n?

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So log(70) would be 7, right?

golden abyss
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no... log(70) is some irrational number

torpid rain
#

Oh

golden abyss
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log(100) is 2 because 100=10^2

torpid rain
#

Ohhhhhhhhh so it's square roots but instead of finding the number you're finding the exponent

golden abyss
#

yeah

torpid rain
#

Ok I get it

round geyser
#

Type I is like an onion one layer and one layer

round geyser
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Log in a log

round geyser
#

Why does this won’t work in Rational root theorem

echo sinew
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The rational root theorem always works, otherwise it wouldn't be called theorem (as long as its hypotheses are satisfied, of course)

uncut mulch
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rational root theorem helps identify candidates for rational roots if they exist

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the only candidates are +-1
and since neither of those are roots,
you can conclude that polynomial doesn't have any rational roots

median kite
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Hey guys

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I wanna ask something

tender questBOT
# median kite I wanna ask something

Asking the actual question right away is more likely to get responses.

Asking "Can I ask...?" or "Does anyone know about...?" doesn't give people enough information to decide whether they can help, and answering can feel like a promise to help with the actual question, which they might find themselves unable to.

median kite
#

Suppose two points on a graph f(x) and f(x+h) then the slope of the line formed by them is given by f(x+h) - f(x)/(x+h) - x which gives f(x+h) - f(x)/h, when we look at this formula of slope of secant line of points f(x+h) and f(x) is literally the formula for average change, when apply limits like, limit h->0 f(x+h) - f(x) / h makes points infinitely closer because the gap between them starts shrinking and we often solve questions and after cancelling h in denominator, we substitute h=0 as a shortcut now when h is literally 0 the points coincided on the graph as difference between them became zero. How does this gives instantaneous change and why is it said that instaneous change is limit of secant line as x tends to 0 which is tangent, when tangent needs two points because it's a line and there is literally one point now because both coincided.

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Am I assuming smth wrong

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Is tangent not line?

stiff sorrel
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Tangent does need two points, yes, instantaneous change, however doesn't reduce these two points to a single one but rather gets them arbirtarily close.

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Otherwise we wouldn't get a tangent line

round geyser
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I assume there will be 4 complete roots

echo sinew
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Yeah, four of the 5th roots of unity

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The ones that aren't 1

round geyser
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If I graph it

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It never touches the y-axis

raw hill
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mhm

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that tells you the roots aren't real

raw hill
valid topaz
round geyser
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Look

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It has to be 4 imaginary solutions

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And plus 2 positive and 2 negative

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a+/-bi

raw hill
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complex/non-real, not imaginary

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imaginary numbers have a real part of zero

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and the roots are in conjugate pairs if that's your concern

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$e^{2\pi i/5}$ and $e^{8\pi i/5}$ are complex conjugates, as are $e^{4\pi i/5}$ and $e^{6\pi i/5}$.

obsidian monolithBOT
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Civil Service Pigeon

round geyser
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What the advanced way to solve it

valid topaz
rough leaf
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finallu i get this integral stuff

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u sub and ibp fibally make some sense

median kite
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That's just makes them one single point

golden abyss
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why is the limit 8.75 as n approaches infinity

valid topaz
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it's 7+π^2/6

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comes from basel sum

golden abyss
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??? answer key says 8.75?

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huh the basel sum makes sense, ig the answer key is wrong

valid topaz
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cause it's wrong

golden abyss
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no, but the answer key does have typos sometimes

valid topaz
golden abyss
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I didn't know about the basel sum so i couldn't solve it

valid topaz
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well now you know, ig

willow bear
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if you say "imaginary number" people will think you mean numbers on the y axis in the complex plane

round geyser
#

Okay

feral inlet
#

dmamn

hot fog
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Found an absolute gem today 🥹

echo sinew
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1?

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That's awesome though

valid topaz
echo sinew
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Yeah it shouldn't definitely 😁

valid topaz
echo sinew
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Indeed

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It's pretty "original", compared to many others I have seen around

valid topaz
echo sinew
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Mmh there's an abs value though

valid topaz
#

yeah it's 1

echo sinew
# echo sinew 1?

Fun fact: just two seconds before sending this I also thought -1. But then I realised lol

raw bobcat
valid topaz
raw bobcat
valid topaz
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if u wanna solve it, go ahead

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but it's answer is well-known

ripe scarab
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is there a calculus section

valid topaz
charred rapids
round geyser
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U know today I found a silly questions on my pre-calc hw

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25^(2x+3)=80^(x-5) with logs

spice crown
# hot fog

idk what is the final answer but it is a non negative real number

spice crown
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well i wasnt wrong was i

valid topaz
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i just stated my answer

spice crown
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well i never said you said i am wrong

valid topaz
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dumb it down 4 me

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plz

spice crown
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my english is prob wrong bro

valid topaz
ripe scarab
round geyser
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How would u solve this 25^(2x+3)=80^(x-5) with logs

raw hill
obsidian monolithBOT
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Civil Service Pigeon

raw hill
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Note how it’s just a linear equation now happy

round geyser
#

Distribute

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2x log (25) + 3 log (25) =x log (80) - 5 log (80)

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2x log (25) - x log (80) = -(5 log(80) + 3 log (25))

raw hill
round geyser
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I factored out

raw hill
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Yeah it’s good now

round geyser
#

x = (-(5 log (80) + 3 log (25)))/(2 log (25) - log(80))≈-15.356

round geyser
raw hill
round geyser
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It’s just graphing log functions, solving log and exponential functions

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Log’s domain will be inside like log(x-5) then D: x>5

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Exponential’s Range will be outside of a functions like 2^x + 1 which R: y> 1

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These three units are the one I got 100 on

raw hill
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nice

snow dawn
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This problem is ungodly.

uncut mulch
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not that bad

rough iron
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anyone got resources to self study for ap precalc exam

snow dawn
rough iron
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also it says i need a class code

snow dawn
snow dawn
rough iron
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thats when the exam is taken

snow dawn
#

I recommend spending about a month on Polynomials and rationalizing functions. If you are really good with fundamental algebra then it could be even less. Then Exponential and logarithmic should not take you that long, so ,about 2-3 weeks. Use most of your time on Trigonometric and Polar functions. Leave about 2-3 weeks before the exam for review. Also make sure to take some mock exams in that time, and practice writing FRQ's between each unit.

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Actually AP Precalc is a pretty easy class, if you understand the material then you should do well

rough iron
snow dawn
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That is literally perfect

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That means you should already have most of unit 1 covered

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Then spend extra time on Log's exponentials and especially trig

rough iron
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I already have some fundemental practice with logarithims and trig so i think i should be set if I basically review the curriculum

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ty

snow dawn
charred rapids
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Really random but:

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A common mistake is to think that
[
\sqrt{x^2} \neq x \quad \text{(in general)}.
]
What is actually correct is that
[
\sqrt{x^2} = |x|.
]

obsidian monolithBOT
willow bear
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it is a mistake to put an equals sign between sqrt(x^2) and x

spice crown
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but mine is better

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cuz i am true and you are 0

opaque rover
viscid thistle
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but what have you tried

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Integration by parts should be it

round geyser
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That’s what I got

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And I used AC method

fringe phoenix
round geyser
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I want to proof that 3/4 is not a solution

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Bc I remembered I got 4 and 3/4

fringe phoenix
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Buddy, you cant just take functions common on both side and cancel them, that's a wrong presentation

dusky comet
round geyser
fringe phoenix
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You cant just cancel out functions

dusky comet
round geyser
dusky comet
#

cause when you have increasing and decreasing functions the inequalties can flip

fringe phoenix
# round geyser

Um x is 4 or 3/4, just put it in to check whether it satisfies the domain or not

round geyser
#

Look

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Drop logs and set arguments equal and solve

fringe phoenix
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Thats a short cut tbh

dusky comet
#

yea

fringe phoenix
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Its not the proper method

round geyser
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How would you do it

dusky comet
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its still gonna be very wrong when inequalties enter

round geyser
#

I’m curious

dusky comet
#

you take antilog, like taking both side in power of the base

round geyser
#

Then the ans key said it’s 4

dusky comet
#

and then with prop of log

fringe phoenix
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Not 3/4

dusky comet
#

you simplify

round geyser
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(x-4)(4x-3)=0

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That’s the factor

fringe phoenix
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Buddy

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This a quadratic equation, you just solve for x

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But

round geyser
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of 4x^2-19x+12

fringe phoenix
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Initially you had log, so you have to put values and check if it satisfies the domain

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Do you know about domain?

round geyser
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ik

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I’m solving and we don’t check domain

fringe phoenix
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Yeah so just check it after putting both the values of x

round geyser
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Cuz that’s last unit

fringe phoenix
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What

round geyser
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Graphing them

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Graphing log functions

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Now I’m solving for logs

fringe phoenix
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Oh yeah thats also one thing

echo sinew
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<@&268886789983436800>

round geyser
#

Huh

round geyser
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Can we factor this?

echo sinew
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,w factor x⁵-x⁴-1

obsidian monolithBOT
echo sinew
#

Seems so, but honestly I don't know how one would come up with that

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Maybe something like "add and subtract" some quantity

round geyser
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,w solve x^2-x+1=0

obsidian monolithBOT
round geyser
#

,w solve x^3-x+1=0

obsidian monolithBOT
round geyser
#

Here is the five solutions

obsidian monolithBOT
edgy aspen
#

How come integral 1/e^x =-e^-x

raw hill
#

But try to look up the question first

fringe phoenix
#

Laws of exponents duh

fringe phoenix
pale anchor
#

how did you guys stop thinking degrees and start thinking in Radians

west ice
#

Remember special angles in radian

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And where they are in unit circle

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Tbh I don't think people can visualize where the angle is in radian a good as in degree

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If I ask where is 1.246 radian on the circle it would be pretty hard to visualize quickly

willow bear
#

pi/2 = 1.57

willow bear
sweet coral
#

what r some shortcuts for solving bayes theorem related ques in high school

echo sinew
#

Mmh I'd say identify properly all the events that come into play

rough leaf
charred rapids
#

Try to get out of your confort zone

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And it will just happen

warm halo
#

Comfort zone...it's just so comfortable mann

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It's like stepping on fire to cross the bridge

valid topaz
#

degrees scare me now

tame agate
#

XD

meager light
nimble wolf
nimble wolf
echo sinew
valid topaz
#

in unit circle, ofc

past jungle
valid topaz
opaque rover
inland current
#

yes but isnt this something the calculater was inventor for

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calcaljustice

round geyser
#

This one is easy

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Can we take distance formula

charred rapids
round geyser
#

No

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I thought of taking x^2 as y2

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And 4 as y1

charred rapids
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Ok but how are you going to get the m (slope) from the tangent line equation?

round geyser
#

I haven’t learned it

charred rapids
#

But does eqn mean equation?

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Or what is the exercise asking?

viscid thistle
charred rapids
round geyser
#

Then we plug these back in

charred rapids
#

But does the exercise ask the equation of the tangent line?

round geyser
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Get the minimums x value and square it

viscid thistle
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hum..

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somehow if you get slope of tangent at that point

charred rapids
#

I dont think your supposed to know how to do that exercise @round geyser , even if you think so

round geyser
#

As part of pre-calc word problems

charred rapids
#

Oh but are you supposed to have hekp from desmos?

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Help*

round geyser
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It didn’t say it

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But I can

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U know that’s should be in calculus

round geyser
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And make line equation

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Take (0,0) and (2,4)

charred rapids
#

No , thats incorrect

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The tangent line doesnt pass through the origin

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And even if it did, it would have been a complete coincidence

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As I said, youre not supposed to know how to do this exercise

round geyser
#

Closest coordinate

icy verge
soft harbor
#

i am new to calculus , so how do i calculate the lim h(x) ?

nimble wolf
round geyser
#

Hey

echo sinew
#

Teacher, leave us kids alone

amber valve
celest mortar
dusk vortex
#

I need help with pre calc 11

raw hill
#

<@&268886789983436800> ^ also check #help-10 as well

dusk vortex
#

Can u help gng

marble quest
#

dont offer payment for help

dusk vortex
#

It’s bad

#

😭😭😭

marble quest
dusk vortex
#

Okay bet

#

Can u help

#

Me gng

marble quest
#

no im dumb as shit

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wait for someone capable

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also you already have a help channel where people are helping you

dusk vortex
#

Wym

marble quest
dusk vortex
#

Yes

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Not being helped

marble quest
dusk vortex
#

Bro

#

Look

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That shit

dusk vortex
#

Yo

ionic temple
#

square the binomial (x-8)
when u do that u will put it in the form (a^2)+2ab+(b^2)

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that'll give u (x^2)-16x+64

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multiply ((x^2)-16x+64) by 8

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when u multiply everything out, u get 8(x^2)-128x+512

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lastly u subtract 3, and ur left with ans D

frosty folio
#

Quick question if anyone's on

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isn't really a math problem more of like a learning problem

hollow widget
#

Just ask the question

long bane
#

guys idk how to graph multiplicities, cross, and tangent(or bounces) like it looks simple but im just rlly confused how to graph it

round geyser
#

That you are in

long bane
deft spade
#

Does anyone know how to graph the first function

copper ledge
# deft spade

Squaring the function gives us a parabola but also notice that g(x)=2√(1-x) so g(x) must be always postive so remove the portion below the x axis

deft spade
#

Wait how come it’s always positive

copper ledge
deft spade
#

OHHH RIGHTT righty TY!!!!

round geyser
#

Here you see

#

Your degree is odd

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And LC is Negative

round geyser
#

Take this

eager meteor
#

prove binomial theorem pls

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cudnt understand any of the stuff on the web

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thx!

#

i will also make a post there

lean rapids
#

👌

carmine orbit
copper ledge
rough leaf
#

you don’t need to know it

round geyser
#

Use pascal triangle

rough leaf
#

exactly

lean rapids
still brook
#

help

fallow roost
#

What is precalculus?

raw hill
#

As per the channel description ^

#

@fallow roost

sour tinsel
#

Quick question - if we're converting polar functions to rectangular coordinates, what is the proper or best way to convert $r=\theta$ to $f(x,y)$? Just naively going for $\pm(x^2+y^2)^{1/2}=\tan^{-1}\bigg(\frac{y}{x}\bigg)$ seems to have domain and range issues. Is there a way to get more than just a small portion of the solution?

obsidian monolithBOT
#

Concomitant

raw hill
sour tinsel
fringe phoenix
sour tinsel
fringe phoenix
#

Um in that question, t is in 3rd quadrant and in unit circle sin t will be the y coordinate

#

Y coordinate is negative in 3rd quad so yeah, i mean this is what i thought

sour tinsel
fringe phoenix
carmine orbit
#

its either induction or combinatorics

round geyser
#

Ok

lean rapids
#

crash course

knotty dove
stoic sleet
#

does anyone have suggestions for better understanding/memorizing the cross product formula?

hollow widget
stoic sleet
round geyser
#

Guys what’s A=Pe^kt

echo sinew
#

Jokes apart, it's an exponential function

round geyser
#

Yes

round geyser
#

How can we relate to example “The radioactive gas radon has a half-life of 3.8 days. Haw long will it take 1 gram to decay to .2 grams?”

echo sinew
#

Well, k = -ln(2)/3.8

Now, if I let T be the requested time, we have the following:

So 0.2 = 1•e^(kT) => kT = ln(0.2)
=> T = ln(0.2)/k

round geyser
#

Hint

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Use two equations

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One for k and one for t

echo sinew
#

Huh? Who is the OP? 🤔

#

I'm confused

mental badger
#

uh...i think the question belongs here? anw, in the resolution, sorry its in portuguese but we can just take the 4 to the other side? even if theres limits there?

raw hill
mental badger
#

oh i see, i saw this section is pre-uni thats why i put it here 😭

echo sinew
#

Sure

#

1 year = 12 months

round geyser
#

Someone said years to months is easier

hollow widget
round geyser
#

Ok

#

First equation is for the k

still brook
#

can someone help with sections 3 & 5?

carmine orbit
raw hill
carmine orbit
still brook
#

help pls

carmine orbit
still brook
#

yes

carmine orbit
#

so where is the problem

still brook
#

i dont understand what csc 0 means

#

like

carmine orbit
#

cosectheta

#

1/sintheta

still brook
#

how does that help

carmine orbit
#

so cosectheta is positive in 0<theta<pi/2 since all functions are positive in that range

still brook
#

so everything is positive except b

#

bc the negative sign is in front of tan

carmine orbit
#

ill brb

carmine orbit
#

now check for the second condition

fluid sorrel
lapis hound
#

if u simplify Q F) from section 3 it becomes 1

old wren
#

follow thí link pls

#

it has a few questions

echo sinew
#

???

old wren
warped shuttle
#

any ideas ?

#

lim x->(-2) (f^(-1)(x)) is basically
f(x) = -2

vocal harbor
opal gust
#

then you can reflect g(x) over y = x to find f inverse

#

or you can find the value of x that approaches y(x) when it reaches -1/2

deft tangle
#

guys i need help with simplifying trig identities

#

the problem is (cscx-secx)(cosx+sinx) and idk how to factor it cuz we had a sub today and they didn’t teach this

willow bear
#

do you have like, the exact problem statement on hand? cause right now it's not clear what you're trying to do at all

deft tangle
willow bear
#

ok, and have you made progress with that simplification so far?

deft tangle
#

because like yk how csc can be rewritten into 1/sin

#

so far i have (1/sinx - 1/cosx)(cosx + sinx) and idk how to move in

willow bear
#

simplify the subtraction of fractions

#

at this point it will be good if you can show some paper

deft tangle
#

do i do it like FOIL method?

willow bear
#

no, not what im asking you to do.

#

simplify $\frac{1}{\sin(x)} - \frac{1}{\cos(x)}$ into one fraction. and as for the other $(\cos(x)+\sin(x))$ bracket, i want you to \textbf{not touch that} for the time being.

obsidian monolithBOT
willow bear
#

understood?

deft tangle
#

oh ok

willow bear
#

also will say once again i will want to see your work on paper.

deft tangle
#

wait i think i got it

deft tangle
willow bear
#

,w simplify (1/sin(x) - 1/cos(x))(cos(x) + sin(x)) - 2 cot(2x)

willow bear
#

correct

deft tangle
valid topaz
#

what is that format 😭

#

and the emojis

woven thicket
valid topaz
#

no one would do that

#

so i shall ping moderators

#

<@&268886789983436800>

drowsy vessel
#

Using chatGPT to 'help' people sully

tired pilot
#

If they wanted chatgpt slop they could just use it themself

round geyser
#

Hey

#

Ann

#

@woeful parcel can you do 2x^3+3x^2-3x-2=0 by rational root theorem and P/Q?

round geyser
winter comet
#

<@&268886789983436800>

chilly magnet
round geyser
chilly magnet
#

I don’t know the cubic formula. Its really long. One moment

round geyser
#

Okat

winter comet
chilly magnet
#

Wdym

valid topaz
chilly magnet
#

Ok well they both work

valid topaz
chilly magnet
#

I didnt know cardano til 5 minutes ago

chilly magnet
# round geyser Show us

Heres the cubic formula. Feel free to try it urself. But im not gonna spend 5 years on this

round geyser
#

So that’s why we should use rational root theorem

chilly magnet
#

Yea

round geyser
#

Good as I learned the shortcut

#

P/Q

chilly magnet
#

Even quadratic sucks

river drift
#

rational root theorem doesn't work on every cubic whereas cubic formula does

#

ofc you wouldn't want to start with cubic formula when other methods would do

round geyser
#

Great

chilly magnet
#

Its just too long. Thats why nobody does cubic equations

#

But quartic formula is even worse

round geyser
#

Yep

round geyser
chilly magnet
#

Whats that

valid topaz
#

galois

chilly magnet
chilly magnet
# chilly magnet Yeah. Its impossible.

There are some cases where it can be solved but it’s been proven that there is no formula that can solve every quintic equation. Only some can. Actually the general quintic can be solved with elliptic modular functions.

chilly magnet
round geyser
round geyser
chilly magnet
#

Hey

round geyser
sonic loom
#

how to get access to the calculus channel

raw hill
fiery trellis
#

can any1 share how to learn calculus urself

#

like a proper roadmap or smth coz khan academy thing is pretty confusing they got tons of diff playlists

jovial thorn
#

read a calculus book

dreamy echo
#

You can start off with essence of calculus by 3Blue1Brown... its not too detailed but good for a start

#

Then Any good theory book... Any good author works tbh

#

I personally learnt calculus through JEE exposure

plush orchid
#

Can anyone help with trig and complex numbers? I missed the lecture cause i was sick!

willow bear
#

$\cos(z) = \frac{e^{iz} + e^{-iz}}{2}$

obsidian monolithBOT
willow bear
#

also $e^{i \theta} = \cos(\theta) + i \sin(\theta)$ (works for $\theta \in \bC$ generally, but is of interest for $\theta \in \bR$)

obsidian monolithBOT
plush orchid
#

Ah i forgot about old Euler, thank you

#

I found one for hyperbolics, although after working it out I’m left with an unsimplified answer

#

My homework says it’s ‘(5*j)/4’

raw hill
# plush orchid

Your first line shouldn't have an $i$ in the denominator.
\begin{align*}
\sinh z &= - i \sin iz \
&= -i \left(\frac{e^{i^2 z}-e^{-i^2 z}}{2i} \right) \
&= -i \frac{e^{-z}-e^{z}}{2i} \
&= -\frac{e^{-z}-e^z}{2} \
&= \frac{e^z-e^{-z}}{2}
\end{align*}

obsidian monolithBOT
#

Civil Service Pigeon

obsidian monolithBOT
#

Civil Service Pigeon

plush orchid
#

AH thank you :0

raw hill
plush orchid
#

Blessed by the pigeons

valid topaz
#

hiii csp

plush orchid
plush orchid
#

cool, i got a final answer although I just cant seem to simplify it

plush orchid
#

motivation 😁

median spear
#

u want to simplify this;

plush orchid
#

its okay, trying it again

median spear
#

$e^{-ln2}$

obsidian monolithBOT
#

ʟօӄɨ

plush orchid
#

thats just 2

#

-2 even

median spear
#

Can be written as 1/2

median spear
plush orchid
#

yeah 1/2 😭

#

I think I’m doing something dumb idk

median spear
#

cuz sryy but ur handwriting is not readable

plush orchid
#

Wait no not that

#

Part B

raw hill
# plush orchid

I have no idea what I'm reading here.
\begin{align*}
\frac{2e^{i \pi/2}-\frac{1}{2} e^{-i \pi/2}}{2} &= e^{i \pi/2}-\frac{1}{4}e^{-i \pi/2}
\end{align*}

Converting to trigonometric form, we have that:
\begin{align*}
e^{i \pi/2}-\frac{1}{4}e^{-i \pi/2} &= \left[\cos \frac{\pi}{2}+i \sin \frac{\pi}{2} \right]-\frac{1}{4} \left[\cos \left(-\frac{\pi}{2} \right)+i \sin \left(-\frac{\pi}{2} \right) \right]
\end{align*}

obsidian monolithBOT
#

Civil Service Pigeon

plush orchid
#

The final answer is 5j/4

#

So confused aboout it

raw hill
ionic temple
plush orchid
#

Still not sure how to get to the final answer :/

#

I dont think i wrote this down

ionic temple
#

so u can turn both exponentials into trig functions, plugging in pi/2 and -pi/2 where x would go

#

then u just evaluate the trig functions themselves

still brook
#

im crine how is ts wrong

low wasp
#

@everyone i need a discord server for physics so bad

#

or chemistry

river drift
low wasp
#

thanks !!

#

bruh i have to wait 24h to get verified

marsh lantern
#

So 45 degrees

still brook
#

oh

marsh lantern
#

I always assume when they say that, go for nearest integer

#

Unless it specifies the place

lost cliff
#

do you know

#

percents

carmine orbit
still brook
#

hey maybe respond a little earlier

#

but A for effort

carmine orbit
#

🙏

worthy kindle
plush orchid
lost pike
glacial flume
rough leaf
#

cuz using de moivres thm ik whta happens

#

but not when using eulers formula

red rose
#

@rough leaf

worthy kindle
sinful pike
#

that's what im being taught

river drift
#

euler's formula can be stated as $e^{i\theta} = \operatorname{cis}\theta$

obsidian monolithBOT
#

cloud ☁

rough leaf
#

i meant z

#

cuz isn’t z = cos x + isinx

plush orchid
#

aye

dreamy cobalt
#

guys I have the best idea for a year 12 jacket

#

tell me if this is a good idea

#

one one side

#

cos

#

other side

#

wait no

#

one side tan

#

other side

#

arctan

#

hehe

#

get it

#

cuz tan inverse

#

and the jacket inverse too

echo sinew
#

🤔

worthy kindle
plush orchid
#

yous also good with diff equations with complex numbers?

plush orchid
river drift
#

cis is an acronym for cosine + i sine

#

,, \operatorname{cis}\theta = \cos\theta + i\sin\theta

obsidian monolithBOT
#

cloud ☁

willow bear
#

cis is also the antonym of trans

#

which lends some room for puns

rough leaf
ionic temple
#

i wxplained terribly tho 😭

dry verge
#

I thought hyperbolas were related to ellipses when I first saw the formula, so I looked it up and they're all related.

#

I forgot if I ever learned what conic sections were in school, but this is actually pretty interesting.

#

Conic sections sound familiar... maybe I picked it up during my trigonometry class or calculus class years ago.

reef inlet
#

I am trying to prep for a test I have, but I forgot my text book in school.
Can someone send me pics of 4.6 and 4.7 problems from Ron Larson 3e Precalc with limits book?

round geyser
#

How would u do this

willow bear
#

it's extremely unlikely that there would be a nice algebraic solution here

echo sinew
# round geyser

Also, is this the original question? Like, this thing without anything else written? Neither "solve this equation"?

frail rampart
#

I kinda need help with the lower one the upper one I’m fine with i was wondering why the k is at the back I’m pretty new to this

cold drum
#

Because it's being multiplied by the sum

daring spoke
steady sentinel
# round geyser

change sqrt to 1/2 power, bring 5 into log to get x^5, and convert to exponential form?

#

something like that

#

idk

round geyser
#

Yea

#

I thought of square it

#

Making it 10th power

urban kernel
# round geyser

I mean I guess, use the fact that 2x + 8 >= 0, which implies x >= -4. For the logarithm to be defined, x >= 1. Now, we try nice values. Suppose, x = 1. The LHS is √10, and the RHS is well 0. Obviously, the LHS is bigger than the RHS. For x = 2, again the LHS is √12 (around 3.46) and the RHS is around 3.15. The LHS is bigger. For x = 3, the LHS is √14 (3.74) and the RHS is 5. Now, the RHS is bigger. Note that the LHS and the RHS are both continuous (the limit of any function as x -> c is simply the function evaluated at c for all points c in its domain), we can use the immediate value theorem to conclude that these two graphs must intersect between x = 2, and x = 3.
Judging by the options, ig (d) 2.2.
Not sure otherwise.

#

Can't think of an analytical 'nice' solution. I think it could Lambert W function, but the solution seems VERY messy.
https://en.wikipedia.org/wiki/Lambert_W_function

In mathematics, the Lambert W function, also called the omega function or product logarithm, is a multivalued function, namely the branches of the converse relation of the function

    f
    (
    w
    )
    =
    w
    
      e
      
        w
      
    
  

{\displa...
round geyser
#

Ok

urban kernel
# round geyser Ok

It might help to see it graphically. Once you know one or two values, and the general shape of the curve, it is easy to plot it. You will get an idea of continuity, roughly the area where graphs intersect, and all.
In the image, the green curve is the LHS, and the red curve is the RHS. They roughly intersect between 2 and 3, around 2.2.

#

This is reference.

patent owl
#

any tips on indifinite intigration

urban kernel
# patent owl any tips on indifinite intigration

Indefinite Integration is just like the inverse operation of differentiation (It's called an antiderivative for a reason). Just think "differentiating what function would give you the integrand." In MCQ questions, you can make do with his technique (differentiate the options). Substitution and Partial Fraction Decomposition are the most common techniques used in indefinite integration. Learn integration by parts and all. Some trigonometric substitutions (Like weirstrass), and euler's identity, you are all 'set' I guess.

rugged spruce
#

I HAVE A QUIZ FRIDAY AND NEED UR NERDS HELP. It will be on complex zeros and the fundamental thermos of Algebra, Rational functions with vertical and horizontal asymptotes, AND Real zeros of polynomials

ancient inlet
#

attach your image

rugged spruce
#

It’s a bunch of lecture notes so I was wondering if u guys know any good YouTubers that I can watch perhaps on these topics

ancient inlet
#

organic chemistry tutor

#

khan academy

rugged spruce
#

Ok let’s see

ancient inlet
#

send a picture of your homework ig

rugged spruce
#

This is complex zeros and the fundamental theorem of algebra there lecture notes but I don’t understand any of it

ancient inlet
#

for the 1st part

#

you know that you cannot factorise a^2 + b^2

#

you would get imaginary number or aka complex number in the form of a +bi

rugged spruce
#

Is their a vc?

#

We can join

ancient inlet
#

im sure there is

rugged spruce
#

They only got the event stage how they gonna make a math discord without vc

rugged spruce
#

Ok ok imma add u both to a gc so we can vc

round geyser
round geyser
rugged spruce
#

Acccept friend request

round geyser
#

Accepted

round geyser
#

Okay

terse echo
#

can someone help me understand why they use a [ for the point -13.674? i thought you only use brackets when including the point, but on that point it seems like they are equal

lilac lance
#

The question asks for f >= g so inclusive of when they are equal

terse echo
sterile trench
#

I'm not in precal yet but people have told me its suuper hard

#

is it true?

lone temple
#

i saw this on a problem in youtube, applying logarithm definition into limit like this is still right?

lilac lance
#

Yes due to the limit property lim (x->c) of f(g(x) = f( lim(x->c) g(x))

#

Limits can come inside composite functions

#

As long as both the limit of f and g as x approaches c exist

velvet cape
#

Trigonometry is a nightmare for me tho 🙏

rare ferry
#

What is considered precalc

carmine orbit
rare ferry
carmine orbit
uncut mulch
#

basic algebra, geo

#

pre-calc builds on top of that

carmine orbit
#

yeah

#

topics like sequence and series binomial theorem may help

gloomy vector
# round geyser Take my notes

I really like your notes! Should I take notes like this for these theorems once I study them and color code them? I have a really good memory though.

round geyser
#

Sure

carmine orbit
round geyser
#

Yea

carmine orbit
round geyser
#

With Cec, Sec, and Cot

floral veldt
#

I think something must be wrong

#

Because if U sub n=2 in both sides it doesn't work

valid topaz
floral veldt
#

Mb

round geyser
#

Can we factor

hollow widget
round geyser
#

What will happen if I factor x^26

hollow widget
#

You can see the factor as x^24/x^24 + x^25/x^24 + x^26/x^24

round geyser
#

x^2+x+1

#

Ik if we factor x^24

#

We can get negative exponents

dry verge
#

We could do a more complicated answer, but it would be more inconveniant than doing x^24(x^2+x+1). And mathematicians like to be as lazy as possible.

#

Now that we have x^2 + x + 1 = 7, it's much easier to factor and solve.

hollow widget
#

and make sure it’s not 0

#

But it won’t be

round geyser
#

Let’s cross multiply

#

and rearrange the term

#

From greatest to least

#

x^26+x^25+x^24=7x^24

#

x^26+x^25-6x^24=0

#

Set y=x^24

#

It’s now

#

y^2+y-6=0

#

(y+3)(y-2)=0

#

y=-3, 2

#

No -3 since the radical can only have a positive ans

#

it’s 24th root of 2

uncut mulch
willow bear
#

(x^24)^2 = x^48 ≠ x^26

willow bear
#

what you say afterwards is bull

#

confidently wrong too

bronze canyon
#

x^26 = x^24*x^2 = x^(24 + 2)

#

final answer's correct tho

weak moth
#

Why does this work I was playing around with first principle and stumbled onto this

jovial thorn
#

I had to use l'Hôpital for this

weak moth
#

a^h

willow bear
#

$\lim_{h \to 0} \log_{\frac{h}{x}+1}(a^h) = x \ln(a)$

obsidian monolithBOT
willow bear
#

is this what you wrote? @weak moth

weak moth
#

Yes

weak moth
#

I still don't understand where e comes from

dawn breach
#

I don't really understand what are you trying to do, derive your limit result? you can just inverse steps

weak moth
willow bear
#

why not just write log_2(x) as ln(x)/ln(2)

weak moth
obsidian monolithBOT
#

Ðɾαɠσɳ

round geyser
#

Ann

round geyser
willow bear
#

now it's correct, except that one of these values has to be excluded based on the original equation.

round geyser
#

24 factors of 0 1 factor of -2 and 3

willow bear
#

how did -4 and 3 come now

round geyser
#

(x+3)(x-2)

#

I mean 2

willow bear
#

-3 and 2.

round geyser
#

Okay

#

Is it 24 factors of 0 1 factor of 2 and -3?

round geyser
willow bear
#

but you discard 0.

round geyser
#

Yes

#

So it’s 1 factor

remote imp
#

does anyone have precalc notes

#

im gonna try for the testout

#

but my notes are kinda unorganized

round geyser
#

Okay

round geyser
rare ferry
#

What’s the difference between ln and log?

raw hill
#

you can google this

#

In short: ln is always base e

#

log usually means base 10, base e, or base 2 depending on context

rare ferry
#

I think I get it

raw hill
round geyser
chilly magnet
rugged spruce
#

Asian people are so smart bro thanks that one Asian tutor that helped me I can finally say I am getting the hang of Precalculus. Literally just search the topics on google they teach u better than ur professors

rare ferry
#

But what if it’s true?

jaunty widget
rugged spruce
#

I meant it in the most respectful way but I get what u guys are saying

flat relic
#

Hi, I'm currently doing calculus, but I found out that many students learn parametric equations in precalculus. Even though my calculus textbook covers them a little bit, should I go back and learn them more in-depth?

true geode
#

What your textbook is covering should at best be the "in-depth" you're referring to

#

They do appear in Calc II as a part of differential calculus, apparently, so I'd suggest having a brief look:
https://tutorial.math.lamar.edu/classes/calcii/parametriceqn.aspx for instance

flat relic
#

Thank you!

terse elbow
#

can someone pls help me with number six?

#

i’ve been stuck for quite a while 😔

polar torrent
terse elbow
#

i’ve tried to turn everything into cos

#

but i don’t see how it can become sine

polar torrent
#

how did you do that?

#

i assume by separating them into two terms?
LHS= cosx+1

terse elbow
#

yes

polar torrent
#

why dont we bring in cos²x

#

since we need to get sin²x

#

and to do that we can multiply and divide with 1-cosx

terse elbow
#

how do u know it’s 1-cosx and not cosx-1?

polar torrent
#

if you go for cosx-1 you would have to multiply another minus sign at the end

#

our goal is to get the numerator to the form (a+b)(a-b)=(a²-b²)

#

if you go for 1-cosx, you'll end up with 1-cos²x=sin²x.
if you go for cosx-1, you'll end up with cos²x-1 for which you would have to multiply a minus sign and get 1-cos²x which is equal to sin²x.

terse elbow
#

yess thanks i got it!

#

so wtv the final answer shud be determines what we multiply it by?

#

to save some time

polar torrent
#

yes

terse elbow
#

thanks sm

polar torrent
#

you're welcome

round geyser
#

Ik

#

n! can be n(n-1)(n-2)(n-3)…

#

Then what’s (n+2)!

uncut mulch
#

apply the same definition

round geyser
#

2-1, 2-2?

jovial current
round geyser
#

No

round geyser
uncut mulch
#

wdym by 2-1, 2-2

round geyser
#

(n+2)(n+2-1)(n+2-2)

uncut mulch
#

where's the rest

round geyser
#

Like this

round geyser
jovial current
round geyser
#

What’s the inverse of factorial

jovial current
#

After (n+2-2)

round geyser
#

I’m not sure

uncut mulch
#

are you saying that
(n+2)! = (n+2)(n+2-1)(n+2-2)

round geyser
#

Like this

uncut mulch
#

anything more after that?

round geyser
#

I’ll put eclipses

uncut mulch
#

and when do you stop

round geyser
#

Infinity

uncut mulch
#

no

jovial current
#

there’s something simpler

uncut mulch
#

it doesn't go on infinitely

round geyser
#

I’m not sure

#

Since I never learned it

#

I’m just interested in this and would want to try

uncut mulch
#

simple example,

#

how would you calculate
3!

round geyser
#

3x2x1

uncut mulch
#

yes

round geyser
#

It goes to 1

uncut mulch
#

yes

round geyser
#

Aka itself

uncut mulch
#

wdym aka itself

round geyser
#

It’s

#

(n+2)!=(n+2-3)(n+2-2)(n+2-1)(n+2)?

#

Like this

jovial current
#

There was a thing I wanted to say but I don’t think I wanna give anything away

round geyser
#

Ok

#

(n+2)!= (n+2)(n+2-3)(n+2-2)(n+2-1)

uncut mulch
#

no

#

you keep changing what you think factorial does

round geyser
#

You mean

uncut mulch
#

no

jovial current
#

Might I add a bit of insight?

Take 9!, if you rewrite it some way, then you get a number * a factorial of sth else

round geyser
#

Oh

round geyser
uncut mulch
#

no

#

why are you stopping at n

#

if you were asked to calculate
7!

#

upon edit, yes

round geyser
#

okay

#

(n+2)(n+1)n!/n!

#

Now

#

May we cancel n! out?

uncut mulch
#

yes

round geyser
#

Then it’s a quadratic

#

(n+2)(n+1)=20

#

n^2+3n+2=20

#

n^2+3n-18=0

fading gyro
#

i was trying to do this question out of stewart's precalculus and i felt stuck and a little frustrated because although when i checked the answer listed in the book i had reached it at some point, i veered off doing more and more steps to try and factor it further off of nothing but the idea that it seemed like it wasn't completely factored. is there some kind of check i can do to know for certain if i am actually done?

surreal crescent
#

What was the question asking?

fading gyro
#

"factor completely"

#

the answer was ||2(x^2 + 4)^4(x - 2)^3(7x^2 - 10x + 8)|| but even though i reached that i kept trying to reduce it further

surreal crescent
#

Know where to stop with factoring can be hard

#

The first easiest thing to know is that if everything is in one term and all are the products of two terms, it’s good

#

If you have another polynomials like you do here, check if you can factor it, and if not, then stop

#

Factoring is really just a tool in your toolbox, and it only needs to function as much as it serves you, so I would ask your teacher/prof their specific rules for where to stop when factoring

tight wagon
# fading gyro the answer was ||`2(x^2 + 4)^4(x - 2)^3(7x^2 - 10x + 8)`|| but even though i rea...

i’d look at each factor you have, and see if you could reduce each one. This sounds really obvious but i don’t think there’s any other way of knowing where to stop.

When you have that answer, you should look at each factor and ask (as @surreal crescent is saying) “is it useful to factor this any more?”. For example, the first factor in the answer is 2, is it useful to factor this any more? Even if it was a composite number like 10, it wouldn’t be useful to factor it into 5 and 2. Then check the next factor, (x^2 + 4)^4. Again, is it useful to factor any more? This term can’t be factored any more (obviously, as it’s the answer to a “factorise fully” question) but if you were doing working for a different question not solely focused on factorising, this question is what you should keep in the back of your mind.

If you’re trying to factorise fully, the only algorithm you can really follow is:

  • factor out a term
  • check if any factors present can be factorised further
  • if they can, go back to the start. If they can’t, you have finished

There’s no other way to really check it’s fully factorised (afaik).

And, again as Root has said, if you are not trying to fully factorise, but are just factorising while within another question, you just need to keep asking if it’s useful to factorise any further (if you even can factorise any further)

#

holy yap (i hope this helps)

fading gyro
#

yeah, that makes sense! thank you :)

surreal crescent
#

Yeah, understanding how to manipulate an equation becomes even more important when you get to calculus, where equation form can determine ease or even ability to solve a problem

round geyser
#

Yes

round geyser
#

And foiling

#

Since in functions like composite functions you will need to do that

round geyser
#

Will there 3 solution

gusty schooner
#

Hi can you please help me. I am currently learning how to graph ALL of the trig functions and I am currently struggling. Are there videos that HELPED you to graph trig functions easier? Thanks

valid topaz
#

oohhh wait u said that already

round geyser
#

Yep

#

Ik it can be 3

valid topaz
#

||7,3,1||

round geyser
#

7,3 is based on their exponent rules and 1 is just observing

round geyser
valid topaz
#

not that easy to spot

plain bone
#

Hi

serene dagger
plain bone
plain bone
grim rock
#

hey

valid topaz
#

<@&268886789983436800>

carmine orbit
valid topaz
carmine orbit
#

ohhh

grim rock
#

hi guys

outer canopy
#

Yoo

floral dome
#

do yall know what i should study for my unit 1b test idk what to do

#

this is basically what my study guide looks like but i have no idea what im looking at

civic moon
floral dome
civic moon
#

U shuld probably just study limits in general as a whole tbh

floral dome
#

and this is also some stuff my teacher put as review

alpine bluff
#

ur doing stats and calculus in the same class?

#

understand the notation first

#

what does something like this mean in english?

#

if u were to translate it to english terms

rough leaf
#

isn’t that

#

h(x) approaching 2 from the left

alpine bluff
#

yep

#

approaching 2 from the left so approaching x = 2 from the left