#precalculus
1 messages · Page 17 of 1
Get it?
this makes so much more sense
Nice
Yeah
math isnt my strong suit
lol
and im taking intro and precalc 1 at the same time
im going in for cyber security but specifically i want to do system engineering
And you’re in college then?
so my advisor told me there is a flip class where its both
Ah
yeah just started
Yea but like over the summer ive forgotten everything so now im relearning the fundamentals
me or legend?
You
And so im doing practice work on every kind of problem i could face
That’s smart
like the one with pi symbols on it right?
Yep
then yes
???
So i just need help and allat
ok
Correct
i remember the funny things
He’s talking about the 2D real number unit circle
the circle chart with the pi symbols to represent at certain degrees
how do u know the unit circle but not fraction multiplication
Dont question it
Pre calc and calc or statistics is required for me
I already passed algebra 2
ya know
thats a good question
Calc is extremely difficult if you are still shaky on your algebra basics by the end of precalc take stats
oop
I can help you if you want me to explain concepts or help with problems
can you provide more context?
are you doing substitution?
Your questions appear confusing
Im solving for the output
Thats the only context i was given
Take the formula and figure out the output
Do u have a specific input?
Idk broski thats all i was given
Looking for the output
I dont know the domain
I can probably figure it out if i did
I was given notes but they dont really help me
Output probably means range
Besides showing me the types of functions like mapping equtions graphs tables and machines
Considering it’s early precalc that’s usually what they focus on
Yea
Using the word output is confusing though
Okay yea then range
y>0
In the grand scheme of things this means range yea
Anything square root can’t be negative
=
Mb
So sqrt x-4 would be equal or greater than 0
If x-4 is under the square root, then yes
It is
Use parentheses so we know the exact statement
Thats good to know
Theres this other wacky one that seems to be troubling me
X=2y^2
Is x the input or output?
that depends
Input
Ok
Output is 2y^2
So inclusive
Correct
Alright
That step by step process is wacky
How does it work
You turned ^2 to a sqrt?
I squared both sides which cancelled the y^2 into just y
Ooh
Thats kind of confusing
Could you do a more in depth process
Also what if a function isnt under a sqrt
How would the process go
There’s a lot of cases. Not much of a universal process besides analytic reasoning which is a skill you’ll pick up as you go
Idk man
Oh w
hmmmmmm
Bro im strugglin
with what?
?
Pre calc functions
Basically im relearning the fundimentals of functions and all that
And i dont get any of it since i forgot it
But im starting to understand little by little
@red bolt
And im seeing if x=12-y is inclusive or not making it >=0
Isn't that just R
Real numbers is negative infinity, infinity is it not
= is anything that is inclusive
Either way its still a function
sorry i was offline
technically yes
Why technically
to sound smarter
lol
equations are not functions
ruh roh
Hey guys I’m back
Got a 55 on a 10 question quiz
So thanks for helping, I would’ve gotten a zero without you
Hey guys I’m self studying pre cal. Does anyone know whether khan academy is good for that
Id say its pretty good
anyone know why it say's I used the wrong variable?
I've done a lot of it and now school started and I whold say it's really helpful
Ok Ty
You don’t need the y= part
oh shoot how did I not see that. Thanks
Np
So i know how to find doubling time but how am i supposed to with just this graph?
😭
Nah bruh they done did me dirty 😣
puro mexico
what is the name of that formula again ?
!memes
🥲 i just used it
just send the question
or not
quadratic formula
Say that your head is the origin with your hands being a parabolic curve and your hands are above an imaginary line that is laying on your head. You could use the quadratic formula there to determine how far your hands are from your head
is it just me or do the guyt's arms in that image above form a parabola
nah, its cosh
Guys i dont get this, i don’t understand how im supposed to find it through the origin
Wait was that deleted ? Bro i dont need an answer i just need some sort of clue
Well dont tell me the answer , i just need some light help
What
Well if you know what type of general equation a graph like this has, then try plugging in the points. Also think about it’s y intercept and the constant your are adding to your equation
Hi! I have some questions about pre cal. Dm me!
I FOUND IT!
Ahdlgodfmtmprph
Lets goooo
My work is never well organized 😭
The messier the most likely im finding it
Y= -8(1/2)^x+8 💪
$x^2-9 = x^2 - (3)^2 = (x+3)(x-3)$
dimpledoink
I think the last two boxes are both 18 because you use the formula "i+n-1" where i = top number, n = bottom number when finding the number of terms in a series. (19+0-1=18).
Convert x²-9 to (x+3) (x-3) and multiply the other fraction by (x-3). Then add the numerators and simplify as much as possible
Just realised you posted the message yesterday💀
if you want help you'll havae to post the problem(s) you want help with
does newtons method uses linear approximation?
how it all connected
where is everyone
I typed 24 and 25 and it still marks it wrong
Is homework being picky or am i straight up wrong? This is supposed to be simple
Perhaps you meant 2024 and not 24?
howdy Im doing running start going into precalc
anyone tryna help me w a lowkey basic but making me feel stupid question for precalc
nobody 😦
i did
but i struggle at the x and y intersect part
can u show me what u got?
what u get?
can't cope up with calculus
use mvt: $$\frac{\sin(b)-\sin(a)}{b-a}=\sin'(c)$$ for some $c$
layla
he did it in #calculus haha
he crossposted it here
oh lol
can someone pls explain how to find B
i need some help with these. ik there’s a trick or rule that im forgetting about
Was I able to to answer this correctly?
No, you didn't isolate the absolute value first.
I think we're good now 👌💯
My textbook was showing me a different way - still got same answers tho.
excuse me, what is an rF value?
Hi #precalculus
(I’m merely guessing that this question is appropriate for here….)
I have a question about terminology:
Given two functions which are composed into each other, we know that this operation is not generally commutative. So we may distinguish between f o g and g o f. What do we call the function on the right, and what do we call the function in the left?
For context, other non commutative operations have names for their last and right sides. Minuend vs Subtrahend and Dividend vs Divisor, etc.
source on that image. https://kids.britannica.com/kids/assembly/view/200345#:~:text=In an addition equation%2C addends,multiplied to give a product.
All parts of arithmetic equations have names. In an addition equation, addends are the numbers that are added together to give a sum. In a subtraction equation, the subtrahend is taken away from the minuend to give a difference. In a multiplication equation, factors are multiplied to give a product. In a division equation, a dividend is divided ...
Hi everyone, can someone please explain to me why these graphs intersect at three points?
i'm no expert but i think it's the same values from intersection 1 to 3
Thanks for the reply, but I want to ask why it intersects in 3 points instead of 2
<@&268886789983436800>
You are using the wrong rule here.
Essentially this means that if |u| is greater than or equal to any positive value, it is less than that negative value and greater than the positive value.
I think the middle point is trying to denote the midpoint.
If that is the case
I found out why, thanks
would this be a jump or a hole
Does it look like a jump or a hole?
oop that sounds worse than I thought
the lines are not meeting meaning it's a jump
lines "jumping"
what
If the lines are not meeting it's a jump, i don't think thinking of the open/closed circles is a good idea
$x^3+5x^2+6x=0$
Arcturus ⬡
can someone explain how to find the solution to this using the cubic formula?
does it say to use the cubic formula?
or can you use anything
because if you just take out x you can just factor
I know, I'm using this as an example problem
Mostly because I tried to do it and ended up more confused
I failed to read and it resulted in over a page of work and a lot of research
oh ok
The ... cubic formula?!
The depressed cubic formula
oh hell nah why
I'm actually not writing it out for you
but essentially, I can simplify this question into
this is the cubic equation, the cubic formula rearranges the function to solve for x
$\bigg(x+\frac{5}{3}\bigg)^3+\frac{-7}{3}\bigg(x+\frac{5}{3}\bigg)-\frac{20}{27}$
Arcturus ⬡
The depressed equation
That is the long form, give me a moment
$x=\sqrt[3]{\frac{-q}{2}+\sqrt{\frac{q^2}{4}+\frac{p^3}{27}}}-\sqrt[3]{\frac{-q}{2}-\sqrt{\frac{q^2}{4}+\frac{p^3}{27}}}$
Arcturus ⬡
I still don't understand why
this is one of the two forms that the depressed cubic takes, where the function is t^3+pt+q
(x+5/3)^3 is t
all cubic's can be depressed, and it makes solving otherwise unsolvable cubic equations "easier"
I'm not sure I want to even witness the quartic formula yet
there is, importantly not a quintic or beyond
it's several times longer
actually, there is not a finite quintic or beyond
truly a nightmare
luckily?
I know, I meant like read it and figure out how it was derived
or maybe not
that means that the formula for the quintic and beyond could be an infinitely long formula
Yea I'd be interest too, what organ did they have to trade to the devil for that formula?
Leibniz's, Euler's, Pythagoras', and Newton's brains /s
“I don’t understand what I have to do in this exercise. Can someone help me?”
you have 2 functions, f and g, and they form lines in a 2D plane.
when you graph it out, you find the area they enclose
@cinder valve not quite sure what you're trying to do
f(x)=2-x-ln(x) and you've found the roots of this function. U then separated the function by it's roots and graphed 2-x=ln(x). You want to find where f(x) intersects that?
is that what u mean?
I found that, I needed to demonstrate there is a real root
For something that I have to do later
To aproximate the root using successive approximations, tangents and secants
<@&268886789983436800>
But... if you could solve for a real root, the root definitely exists?
I guess, it's not the point of the exercise
Maybe it's still only an approximate value
What is the definition of vectors? In my physics class, it is said to be a quantity to represent both magnitude and directions, while my math book defines vector essentially as a n-tuple and without mentioning to neither magnitude nor direction.
neither are technically correct
you would define a vector as any element of a vector space, while elements of the vector space satisfy some properties, in particular you can add vectors and multiply them by scalars
a vector doesn't have to be an n-tuple either, continuous functions are vectors too
Just use newton method then
How do you define a vector space if the definition of a vector is dependent on it?
a vector space is a set and elements of that set satisfy what is known as axioms of vector space
any set that satisfies these will be a vector space
Oh that way of defining it is so weird i guess it's more general?
well it looks weird untill you meet more exotic (and useful) examples of vector spaces
in particular studying vector spaces whose elements are continuous functions is pretty important as far as applications in e. g. physics and differential equations go
and it's pretty natural that you can add functions and multiply them by scalars, there's the zero function and f + (-f) = 0 (the zero function)
wtf lmao
a continuous function is a vector now ._.
when your vectors are n-tuples, you can construct matrices and diagonalize them, such that the matrix has very simple diagonal form which is easy to work with in all applications
fourier transform does similar thing, but it diagonalizes some complicated function into a sum of simple sines and cosines
Hey guys
The dashed line is me halving it to focus on the interval 0<theta< pi/2
Don’t need the answer just something to move me along **
Cus i am stumped now since i dont know how to find max range
I attempted a few more and got the thing wrong but i got half the points
Since my pi/4 was correct but it was the amplitude v^2/g
That would be max range
won't the maximum range be $\theta = 45$ because sin(2*45) = 1 ?
David
<@&268886789983436800>
IKR? Thats what i tried
But it marked it as wrong
Good to know i wasnt tripping thinking it was 1 too
Pls
I need help
My teacher had a mental breakdown trying to explain this she was just talking to herself the whole time and never ended up helping me
How do I do 3. 4.
These are the choices
I don't understand all of this yet but that made things way less confusing, thank you.
If only my teacher told me that the magnitude and direction definition was sugarcoating.
Is there any easy way to evaluate this summation?
conjugate shit and then it'll telescope
Could you explain this in a more detailed way?
multiply numerator and denominator by $\sqrt{i}-\sqrt{i+1}$
elon mask
sqrt(i+1)-sqrt(i) slightly better
just trivialities 
but yeah you should get something which obviously telescopes, and the problem is pretty much done
Ty for nothing
Thanks for your help : )
Thank you for helping
how lol
doesn't n have to be greater than 30 for the central limit theorem to apply?
It doesn't say that the parent distribution is normal either
That's more a question for #probability-statistics.
I'm no expert, but (i) "30" is at best a rough rule of thumb, not a hard cutoff. (ii) the point of the central limit theorem is that it applies no matter whether the individual experiments are normal distributed, so long as they're independent and identically distributed.
Ok sorry ive added it to my channel list
I'm still.in high school
And the stats was in uni section
qathh
Hi, what is a_n as n approaches infinity?
Here's a hadwavy way to approach that:
- Obviously the limit will be somewhere between a1 and a2.
- But it will also be somewhere between a2 and a3.
- And since everything is linear it will be the same place, relatively speaking, between a1 and a2 as between a2 and a3.
- So there must be some constant k between 0 and 1 such that the limit = a1 + k(a2-a1) = a2 + k(a3-a2).
- Since you know a1, a2, and a3, you can solve for k.
Someone can help me, please
A function is bijective iff it is injective and surjective
u all are rlly smart
How do I show if it is injective and subjective?
suRjective.
Injective -- if f(x) = f(y) implies x = y for all x,y \in Dom(f)
For surjective you need to specify the codomain first
@digital mirage
how to get at that circled step from the last one
First, it appears, you have to invent an alpha out of thin air ...
hwp they get to that underoot 169/4 thinG
did you read the link i sent you?
and how that underoot entered the game ?
169/4 = (13/2)².
ya , i know this bruhh . but how to get that full step ?
hello ?
plzz help me out
ya i overlooked it sorry , i m looking , may it help
So I had a question regarding performing row operations on matrices.
How to correctly identify what row should we perform on first? Or does it not matter since we're just converting it to row echelon form?
For example:
We're supposed to convert this into the row echelon form and then use that to get a new system of equations to solve the equation for a unique solution.
I performed the row operation shown in the picture. The book on the otherhand performed different set of row operation and got a different answer, but since we're both converting the bottom triangle to 0s, shouldn't we have the same answer?
if the answers look different it doesn't mean they are different, especially in linear algebra
The reduced row echelon form ought to be unique, though -- but the calculaton here doesn't quite go all the way to RREF.
Hmm
This is how the book did it
,rccw
Hmm, that doesn't go to RREF either -- but the solution it gets is definitely different from yours.
Yeah, that's what I was concerned about.
Have you checked whether your solution actually solves the original equations?
yeah
they do
oh
nvm
i copied the question wrong
i get the same answer too
but the matrix looks different
Oh, your original matrix is different from the book's. You have a different sign on the 5.
Yeah lol, copied the matrix wrong
also one question @hushed sphinx
if you're finding an inverse of a matrix using row method
then no matter the order of operation
you'll arive at the same answer right?
Yes, you should. A matrix can only have one inverse.
Okay, thanks
matrices are so boring that way
thats pretty smart, thank you
here domain of x in 16 - x^2 will be -4 to + 4 but how to find sinx domain along with it ,
geq 0 means ?
like sinx domain is all real numbers so now what to do , how to combine these both . intersection means , common things in both set , so then domain will be - 4 to + 4?
,
Greater than or equal to
\ what this sign means here , i m not introduced with these short cuts
Ahh sorry just ignore that
It simply means greater than or equal to
ohk
so u mean points where sinx is >= 0 in theinterval [-4 , 4] take those point and and then take intersection ?
Yep intersection with [-4,4] (domain of f+g is dom(f) intersection dom(g))
but how to know sin value from -4 to +4 ?
like sin deals with angle
these are numbers
sin graph has things in pi form (domain ) how to knwo about -4 and +4
hmm the intersection step is kind of done when we restrict the solutions of sin(x) \geq 0 to [-4,4], so the solution set of this inequality is the domain of the original function
pi < 4 , -4 < -pi
oh yeeees , hmm now i got it , sorry that was dumb Q
all these could also be domain , i guess ?
cuz they all giving 0 to 1 value
so now what is domain of sinx here lmaooo
@noble vessel ,
oh yes they cant be
cuz we have limit of - 4 to +4
2π > 4 , -2π < -4 < -π
so 0 to pi is the domain here ?
so [-4,-π] ∪ [0,π]
include the negative values of x as well
but then range of sin x will not be from 0 to 1
sin(x) is greater than or equal to 0 for x in [-4,-π]
.
I was saying you need to include [-4,pi] as well
ahh no that is between [-4,4]
.
so [-4,-π] ∪ [0,π] this is the final ans ?
but pi < 4 so 4 is excluded here , it is bcz we took intersection so now these so [-4,-π] ∪ [0,π] are doamin of both fx +gx after intersection ?
ok ty very much
one more thing to ask ...
[-4,4] *
but if we took 4 in domain , it will be exceed pi and then sin will give -ve value
which is not possible in underoot
no.of solution of this equation ?
Probably 1
is x a natural number or
this info is not given
honestly just use mod 2
Find the vertical asymptotes (if any) of the graph of the function. (Use n as an arbitrary integer if necessary. If an answer does not exist, enter DNE.)
f(x) =3/x^2
wow dr stone irl
anyone able to help me with compostite functions?
🤔
i got the ans
Can someone explain how J came to be about?
Shouldn't the leading diagonals in J be 1, 0, 1?
how is -1, 1, & 2?
both my S and M values are correct but can't figure out J
??
Hi i've got a question, what's the symbol for like "equivalent" in math? I want to write that
f(x) = 5 - x is equivalent to a_n = 5 - n (the question is about arithmetic progression, but it's written in the form of a function)
but im not sure what symbol to use
and im not sure if this is the right channel so sorry about that
Just use words. Do you have such an intricate argument in mind that having a symbolic notation would make it clearer what your line of thought is?
ur username
can anyone help me with this, im takin a quiz rn and i forgot how to do this stuff
If you're taking a quiz, you're almost certainly not supposed to receive external help during it.
Hmm what if I’m not taking a quiz
ok i submitted it what was the answer tho
B I and III
damn
What did you mark?
hmm quite close
i thought it was 2 and 3 but wasnt sure about 1 tbh so i just picked the one with 2 and 3
hmm x-intercept is when the graph crosses the x-axis
As you can see f(x) is positive in the interval (-inf,-3) and negative in the interval (-3,1) thus value of f(x) is zero at x=-3
thank you, I'll make sure to study the stuff before my test I suppose
I think the answer is no.1 but the video says no.2. Pls explain if you know why
it is 1
take the case of x = 1 and check the answer for both 1 and 2, then compare them to the graph
tf
How would one graph cos$(2\pi x) + i$sin($2\pi x)$?
okeyokay
in the complex plane that is
we have $0 \mapsto 1$, $\frac{1}{2} \mapsto -1$, but $\frac{1}{8} \mapsto \frac{\sqrt{2}}{2} + i\frac{\sqrt{2}}{2}$, so how would you map that
okeyokay
you need 3 dimensions ?
no
doesn't work
given $\log_9(x) = \log_{12}(y) = \log_{16}(x+y)$, how to find $\frac{x}{y}?$
baba tū est
my brain is shit could anyone help me learn some things about 1.compostiton of function
can anyone help me differentiate the problem below?
oh you want to differentiate?
yeah
😤
im rlly struggling w precalc im homeschooled but i do classes online i got sent to recovery like 5 times cuz idk what to do 😭
lemma try.
@drowsy beacon hold on I am still looking for solution so do not worry answer when find out the answer.
these are very useful for me
bro is dedicated
Hey quick question dudes does the formula for arithmetic series sum start at n=0 or n=1
actually i think it n=1 cause you counting amount of terms
talkign to myself here basically but there's one for n=0,n=1 or any value you choose but just one i was thinking of was for n=1, bad question i guess lol
Plug in some numbers and see
a sequence (Sn) is said to be bounded if and only if (|Sn| <= k ) where k is a positive real number . so my Q is if this is the case so this means those sequence which have their highest and lowest value between -k and k are said to be bounded . like -k<Sn<k is bounded but -k<Sn< m is not bounded .... ? and if this is the case then why defination of bounded sequence says that Sn is bounded if m< Sn< n exist .....
what are actually bounded sequence
Why would -k < Sn < m be unbounded
The sequence starts at n=1 for arithmetic sequence, and each term is a + (n-1)d
Btw I was talking about iundied’s question
In mathematics, an inequality like this is typically used to describe a range of values for a variable (in this case, Sn). Whether or not it is unbounded depends on the values of k and m and the specific context in which it is used.
Bounded Range:
If there are specific values for k and m such that -k < Sn < m, and these values create a finite range for Sn, then the range is bounded. For example, if k = -5 and m = 10, then the range of Sn would be -5 < Sn < 10, which is a bounded interval between -5 and 10.
Unbounded Range:
If there are no specific values for k and m that limit the range of Sn, then the range can be unbounded. This means that Sn can take on values that are not restricted by any specific upper or lower limit. For example, if k = -∞ (negative infinity) and m = ∞ (positive infinity), then the range of Sn would be -∞ < Sn < ∞, which is an unbounded range because Sn can take on any real value.
In summary, whether -k < Sn < m is unbounded or not depends on the values chosen for k and m. If specific values are provided that bound the range of Sn, then it's bounded. If no specific values are given, and the range is not restricted, then it's unbounded.
my q is why this theorem exist if we have general understanding that Bounded Range:
If there are specific values for k and m such that -k < Sn < m, and these values create a finite range for Sn, then the range is bounded. For example, if k = -5 and m = 10, then the range of Sn would be -5 < Sn < 10, which is a bounded interval between -5 and 10.
why we need this theorem which focusing on special case of -k to + k
Who ever needs help with trigonometry ping me
Probably this theorem will be used in some proofs for limits, which have absolute value in their definition
ohk
@cinder veldt
Guys how can i better my algebra skills
Like is there a website for that? My skills are starting to become better as I learn more calculus but I want to be able to ace calc because of my first failed test. If the concepts remain as easy as they are now then its just the algebra i need
you got the first one
do the same for the second
that didn't make sense
but if you're looking for a website use khan academy
Can anyone remind me how I would solve this problem
trig identities
idk how to do those
first of all what identities can you recall
well I have them infront of me . I just dont know how to use em. (Reciprocal Identities, Quotient Identities , Cofunction Identites)
what can you say about tangent
opp/adj
in terms of sine and cosine
uh, idk
$\tan (x) = \frac{\sin (x)}{\cos (x)}$
Transparent Elemental
ah ok
Sorry, main point, want to strengthen my algebra skills for calculus.
Okay thanks
difference b/w limit point and limit of sequence
plzzz tell me in simplest way possible , i cant understand the difference
limit has all the seq members closer to it after some n; accumulation point has infinitely many, but not necessarily all
limit point and limit for seq are the same
really ? like almost same or exactly same ?
my bad, just replace the accumulation point with the limit point in the answer above and forget about limit point and limit being the same
i m asking about limit point vs limit of a sequence
@onyx drum
limit of a seq has all the seq members closer to it after some n; limit point has infinitely many, but not necessarily all
Hello, can someone help me factorize this : mx^2 -(2m-1)x + m -1 without using delta.Thanks
Does anyone have any conversion sheets i can memorize?
Conversion sheets?
wdym by conversion sheets?
like unit conversions?
Progameyen
Progameyen
Is it ok if I ask help for assignment
That is true only when x is a multiple of 120°.
On the other hand 2cos²(x) = 1 - cos(2x) for all x; that looks somewhat like your equation :-)
how 3 point is true (2-e , 2+e ) belongs to set {1, 2, 3 }
The point 2+e/2 (where e is some small positive real) is an element of (2-e,2+e) but is not an element of N.
sorry i was asking for point number 3 ,
how point number 3 is correct
Same, though. No matter which positive number you choose for e, the set (2-e,2+e) will always contain a number (many numbers, in fact) that is no one of 1, 2, or 3.
@hushed sphinx so this set contains only 1, 2 , 3 , and there is no numbers in between ? so { } means this ? like if instead we used [ ] or ( ) that means infinite numbers are there b/w 1, 2,3 like 1.2 , 1.3 etc
this is what ur saying right ?
The notation {1,2,3} means a set whose only elements are the exact numbers 1 and 2 and 3.
ohhk thanku u so much
The notations (a,b) and [a,b] are quite different from that.
hmm these notions means there are infinite numbers b/w a and b
If a<b, there is always an infinity of numbers between a and b. The question is whether those numbers are elements of the set we're talking about. The interval notations (a,b) and [a,b] are ways too say they are, but list notation {a,b,c} doesn't say any numbers other than the ones explicitly written down are elements of the set.
Can I simplify this more. And how if I so.
You could write y²(8y³-2)(5-5y³) where y = e^-200t -- but whether that constitutes a simplification is up for debate.
Or perhaps even -40y^8 + 50y^5 - 10y^2.
Ok, I see thank you
Guys I need help with deriving this function, I know the correct answer to it but I'm trying to do it myself
With respect to x of course, R is a constant
*for sufficiently big T
How can you always factorise f(x) - f(a) by x-a?
I've already formally proved this by setting x = log_b(c) and y = log_b(a), but is there any nice intuition for it?
@viscid thistle
i don’t take pre calc
what's the function?
you always need plug f(x) given into the function and solve
No it’s like a simplifying technique for when you calculate the derivative at a given point
its not a simplifying technique unless you know what f(x) is
For ex, f(x) = x+1/x^2+x+1 and a is -2
so many pings at the same time ahh
My friend has a "degree" from harvard university and he sent me this.
Anyone to solve it ?
I don't see how any of those can be said to be "PREcalculus".
I’m stumped ngl
(fog)(x) = f(g(x)), won't be able to find (fog)(x) if g(x) is undefined
idk why but i like integral more than diffrential
Is E considered a Square matrix?
C and G are, since they got the same number of rows and columns
a 1x1 matrix is square
and what is a scalar matrix?
something akin to a horse bicycle?
huh
that's not a term i'm used to seeing
aight np
it looks like some people use it to refer to a matriux that is equal to kI where k is a real number and I is the identity matrix
aight
i think the idae is that it's a matrix that "acts like" scalar multiplication
I see
since it's a scalar multiple of the identity matrix, which is both a left and right identity for the vector spaces you'll encounter at this level of your studies
so you'll need to learn that definition even if you'll never encounter it after the class you're currently taking lol
gotcha lol
Well ... the ring of n×n matrices is an unital associative algebra over the scalar ring/field, and it's pretty common when talking about unital algebras to identify the underlying ring with its image in the algebra ... especially when that image is injective.
I'm testing my understanding of multiplying complex numbers by explaining it in my own words
Is it correct to say that multiplying z by another complex number w results in a phase shift?
I'm having trouble concisely describing the result.
The multiplication creates a new complex number, m.
m = z*w
arg(m) = arg(z) + arg(w)
|m| = |z||w|
Can anybody explain to me why I got the answer wrong? The correct answer to this question is -1.2
I guess I have done everything right, but the answer is wrong
the last step is wrong
actually idk
My professor gave me this great tip about the unit circle that I've forgotten but I did write something down to remember it. Sadly, I don't think it was enough.. Does anyone have an idea of what I meant by this?
"For the unit cirlce, think about the xa nd y. Is it big x and small y or small x and big y"
are you talking about x and y axis or what ?
honestly I can't tell
I think this might be something for just tan
Cause it doesn't make sense for sin or cos
ohh yes that is unit circle is tan (theta) = y/x
this is the definition of unit circle
okay but this is the definition
right
which I don't think was what he was trying to show
oh well
I'll just try to email him
why is the derivative of a vector of constant magnitude orthogonal to that vector
You mean x=1?
$\frac{d}{dt}(c) = 0 = \frac{d}{dt}\left((x(t),x(t)\right) = (\dot{x}(t),x(t)) + (x(t),\dot{x}(t)) = \\ = 2\left(x(t),\dot{x}(t)\right) = 0$
Transparent Elemental
anyone have a video link how to solve this? i cant find something similar
you need to show two complex numbers are equal
when are two complex numbers are equal?
How does ^3sqrt(x) even works?
Are you sure you're in the right place with that?

yes'
hey can i get tips on factoring x^8 + 8?
i feel like there's something i could do with roots of unity but i can't get it down
you can find the complex roots of x^8 + 8, and pair them up to get a factorization over R
if that is what you want
They won't be particularly nice anyway, since 8 is not a perfect eighth power. (Being a perfect third power doesn't really help us, alas).
they won't be nice but how would i find them?
They are the eighth roots of -8, so take the eighth root of the modulus and divide its argument (± multiples of 2pi) by 8.
eighth root of the modulus as in take the roots of 8 and make one negative?
i know this might be a stupid question. but i was never formally taught roots of unity so i'm a bit lost
i understand the idea behind taking the root of the modulus and the argument but idk the mechanics
No, just $\sqrt[8]{8}\cdot e^{k\pi i/8}$ for odd $k$.
This is not really roots of unity, just De Moivre.
Troposphere
ah okay, thanks!
yeah i'm even less familiar with de moivre
just double checking: so $(x-\sqrt[8]{8}\cdot e^{\pi i/8})$ would be a factor?
peachscribbles
Yes, if you're okay with complex coefficients in your factors.
Otherwise you'd multiply out $(x-\sqrt[8]{8}\cdot e^{\pi i/8})(x-\sqrt[8]{8}\cdot e^{-\pi i/8})$ to get a real quadratic factor instead.
Troposphere
There are 8 different roots.
based on the different values of k?
Yes.
Ok thank you anyways
I found what I had done wrong, the part where I convert "4x^2-3x-1" to "(x-1)(x+1/4)" should be multiplied by 4, that's why the answer is four times the correct answer lol
1/2 = 2^{-1}
Bob.
thank you
why they give this info taht f(x) = 0 when x= 4 . what is the need of this info here ?
second Q is , when they are saying f(x) = |x-4|/x-4 when xis not equal to 4 then how they are taking this |x-4|/x-4at x=4 to find the limit ?
k
I have ap calculus I need help can anyone help me?
Guess i screwed myself over
how do i use it?
Do you know what is the answer for (f-g)(x)? If you know please reply and write it here
So we can go on with your question
@pine geyser can u help me?
yes whats your question
its a pre-calc question
ok np
so to find the answer for the first one, do i just solve the equation?
then for the second one do i substitute 5 for t?
i guess by "intially" they mean that the month is 0 right? P(0)= your answer
yh.
it is 5 years and the function "P" is based on month, so we should convert year to month which means 5 * 12(12 months per year) and we will write P(60)
and how do i solve the last one
lemme think for a sec
kk
does this function even have a limit? Im not 100 percent sure what it means by the end of the population
it goes to infinity and it doesnt approach anything as far as i know
I dont think it has a limit the question didn't state so.
idk maybe
so how do i put that in a answer?
oh no im so sorry, i havent studied the limits of infinity
I dont think its the limit of infinity then because we didn't study that too.
hmm
one of the ways you can find the limit of the function is using derivative
L'Hôpital's rule (, loh-pee-TAHL), also known as Bernoulli's rule, is a mathematical theorem that allows evaluating limits of indeterminate forms using derivatives. Application (or repeated application) of the rule often converts an indeterminate form to an expression that can be easily evaluated by substitution. The rule is named after the 17t...
this is somthing i havent learnt yet
why they give this info taht f(x) = 0 when x= 4 . what is the need of this info here ?
second Q is , when they are saying f(x) = |x-4|/x-4 when xis not equal to 4 then how they are taking this |x-4|/x-4at x=4 to find the limit ?
in the neighborhood of x = 4 f(x) is given by |x-4|/(x-4)
How would I be able to solve this?
guys i got a cool and fun question
if you knew that f(x) = 4x^n-1
n is a true positive number
and if u knew that f'''(x) = a
also "a" is a true positive number
find out how much is a-2n
got some tricks in it
its fun to solve ngl i had so much fun solving it
what's a "true positive number"
derive it normally, 4(cos2x)(2)+1/x ln10 +1
you mean an integer
its either 123457 to infinity
idk my main language is arabic
its a positive number, a one whole number
not 0.smth
integer
yes, i am telling you, that's an integer
good to know ye
it's not that interesting, for a moment i thought it would require number theoretical techniques, but then i noticed the constraint
it is kinda interesting
its fun
nothing too serious
also kinda above the level of this channel
this is precalc, people in here aren't expected to know differentiation
i did not find any other channel
dude literally asked for help
here
sadly, lots of people ask questions in the wrong place
no problem
solve it dude
just solve it
i want u to have fun
you
i don't think iut would be fun for me
ok then how much is it
is it 18?
no
almost 18
u got close
i think you did everything correctly, review your answer and check for any mistakes in the numbers
Always enjoy maths
I always enjoy it
I already solved it
Aight, it turned out to -8sin2x+1/x+1
ye its 16
u derived it again?
well you can't really tell if the (n-1) is in the exponent or if its (4^n) - 1
gettin 18 the other way
the trick is simple
isnt the third derivative 4(n-1)(n-2)(n-3) x^n-4
and thats equals to a
depending on that, a is multiplied by x^n-4 but where is it?
meaning its multiplied by 1
so x^n-4 should be x^0
n=4
yeah
hi, is it possible to turn any sequence's recurring formula into an explicit formula via some method?
specifically this
you can just google how to solve recurrence relations
didnt know they were called that
can somebody please walk me through this I have a chapter test next week and don't understand how to get it from a graph
Can you share how u got to the conclusion of 17
17^2 is 289 bro what u on
who wants to help me with integration
like study with me
writing a really important test in 2 days
What topics get covered in UK A-levels?
I don't know where to start advanced stuff
For the first two blanks, where do you think the graph intercepted with the x?
pretty sure you can just use u-substitution to calculate that
figured it out ty thp
solved it, is the answer meant to be really ugly tho?
cause i got a really ugly answer
https://www.youtube.com/watch?v=ngnH0ZSyPfk my reference video, you prolly can use this to calculate out a solution
Integral by partial fraction & completing the square,
check out @bprpcalculus for more calculus tutorials.
T-shirt: https://teespring.com/derivatives-for-you
Patreon: https://www.patreon.com/blackpenredpen
but it basically uses u-substitution to split the integral into two components, one with an ln integreal and one of a tan^-1 integral
hopefully this helps!
@knotty shard do you still need help w/ this
ok np
Can you share the solving steps please
Sure, not immediately tho
Ill share soon tho
ok
how familiar are you with limits in general
well ok then
as x goes to infinity, what happens to 9-x^2?
@knotty shard wait why did you just delete all your messages???
you asked why $\lim_{x \to +\infty} \pm \frac{1}{9-x^2} = 0$ ...
Ann
why do you deny that you asked it though...?
Alumi please stop trolling and denying that you asked a question
you are either trolling or just very strange
the question is perfectly legitimate and in no way a "taint to the channel"...
sin(1) isn't minuscule, is it?
it's around 0.57 or something.
,calc sin(1)
Result:
0.8414709848079
oh, i must have been thinking of cos(1).
sin(1 radian) is about that much.
it is the default in calculus
you need to stop obsessing over which questions are "great" and which are "taints"
good job doing EXACTLY what i told you not to.
ffs
my reasoning for what?
you can view it as a criticism towards your attitude/behavior.
anyway if you really want an explanation of my reasoning: such dichotomies help nobody and only waste time and mental effort.
jesus fuck you're overthinking it
lol
How come the limit as x approaches 0 of sinx/x = 1? I know that if I do L'hopital rule ill get 1 but is there a way to get 1 without doing that?
exactly
what exactly is that?
sandwich/squeeze theorem
do a search on it then
another on
limit sin(x)/x squeeze theorem
How tf did she work this inequality I can’t get it at all
Do u flip the sign when u take reciprocals?
you only flip when multipling the inequality by -1
she didnt flip the sign she just multiplied .007 and took out the n+1^3 nothing special
Wait does that rule apply to divison as well? I forgot
wdym?
The sign flip
Like if I divided -2 from the left side of (-2x<4)
I feel like I just answered my own questions..
idt so because your also doing the same to 4 and not necessarily multiplying by -1 like if it was x<4 then -x>-4 but for this example it would still be x<-2
multiplied by what?
Yeah it's for both
Just checked
by the n+1^3 then she multiplied by n+1^3
thus removing it from the demoniator and multipling to the one on the other side
so it would be x>-2?
Is it because division is still scaling, but by a value less than |1|?
Yup
I wonder if we can verify this geometrically
Hi, could anyone please help with this. When will solving f(x)=x give all the intersection points between f and f^-1? I've heard that it's when f is strictly increasing but I'm not too sure. Thanks!
How would one find the equation of a parabola if the vertex (5, 0.47) and the x intercepts are 0 and 10
yes
if a graph only goes up or down solving f(x) = x shows where the line meets its flip side
you need to use the given vertex in the formula as y = a(x - h)² + k then use an x-intercept where y is 0 to find the value of a
"flip side"?
flip side can be also known as inverse no?
f(x) = x does not necessarily have the same roots as f(x) = f^(-1)(x)
also a function can be neither increasing nor decreasing and still have an inverse
such functions are often pathologically weird, but they do exist
for example the graph of inverse of f(x)=1/x intercepts the graph of f itself at every point
since f(x) = 1/x is its own inverse
and if you limit the domian to the positive reals, this function is monotonically decreasing over its domain
or consider f(x) = x/2 for rational x, -x/2 for irrational x. this function is invertible but not monotonic. however, f(x) = x occurs when x=0 which sht eonly point at which the function and its inverse coincide
hm, what about f(x) = 1+x+floor(x)? this function is increasing and is invertible (although its inverse has a weird domain)
eh, no the inverse never coincides with the funciton
ok i know this is dumb but what’s the invers of 1/2? is it 2 or -2?
It's 1/ 1/2 = 2
ah ok thanks!
depends on which invers eyou want
cancel the negatives?