#help-33

1 messages · Page 45 of 1

still temple
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.close

marsh citrusBOT
#
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marsh citrusBOT
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azure trench
#

,rotate

marsh citrusBOT
elfin berryBOT
azure trench
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When you take moments about O do you equate those colours

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Why can it not be forces going upwards= those downwards when you take moments

marsh citrusBOT
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@azure trench Has your question been resolved?

twilit grove
#

what is the question asking?

marsh citrusBOT
#
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fair flame
#

Can someone please explain me how the left term is equal to the right term ?

sleek lake
fair flame
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Yeah

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This one

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How is that equal

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Sooo ?

marsh citrusBOT
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@fair flame Has your question been resolved?

marsh citrusBOT
#

@fair flame Has your question been resolved?

marsh citrusBOT
#

@fair flame Has your question been resolved?

fresh oyster
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there is a general solution to the basel problem

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this formula is just because both are pi^2/8

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both of which are very tricky problems

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we can start on the summation first if you do not know about these solutions

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we have the mclauren series for sin(x)

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$\sin{x}= \sum_{k=1}^{\infty} \frac{(-1)^k x^{2k+1}}{(2k+1)!} =x-\frac{x^3}{3!}+\frac{x^5}{5!}+\cdots$

elfin berryBOT
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Cycadellic

fresh oyster
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then we can do this

fair flame
fair flame
fresh oyster
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so

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i had to look up eulers proof

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according to wikipdia

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we can use this style of proving

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to solve the sum

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its all based on the roots

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basically, we can factor the poloynomials roots

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consider the quadratic formula

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you how how the quadratic formula can find the roots

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d(x-a)(x-b)=0 is all possible parabolas with 0's at x=a and x=b

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and we can get to every parabola with these roots because of our d

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so, we can do this for any polynomial

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3rd degree, 5th degree,... 10000th degree

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this will work for all of them

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well

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this approximation is a polynomial

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we use a limit so that we can consider it at finite values, if it works for all finite, we can say it works to infinity

fair flame
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Yeah

fresh oyster
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(although there are some slight errors with this logic, and we have to do analysis for full rigor) but this should be convincing enough that we can do this

#

so, we need to find the factors of the polynomial

#

in this problem, where does sin(x) pass 0?

#

at all pis, right?

fair flame
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in kpi

fresh oyster
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right

fair flame
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where k is an integer

fresh oyster
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so this factorization should make sense

#

this one is /x

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specifically

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and they divide the pi off to get it into x, but its the same idea

fair flame
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yeah

fresh oyster
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so, if we want to directly solve this instead of just applying the general formula and calling it a day, here is the tricky bit

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we need to find the right sin(ax+b) that has the correct roots to get our summation

fair flame
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yeah i think i understand this

fresh oyster
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then

fair flame
fresh oyster
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we take on the massive task of distributing this long product

#

its the same solution method

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instead of sin(x), we need to adjust the roots

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then itll work

fresh oyster
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although

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we can avoid this completely by accepting this

fresh oyster
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this is the basel problem

fair flame
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The (1-x²/π²)(1-x²/4π²)+... Or the -(1/π²+1/4π²+...) One ?

fresh oyster
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i can show you quite easily that this theorem will make the summation easy to solve

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then, if you need, i can prove the theorem

fair flame
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I'm sorry but did u understand my question ?

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I may have misspoken

fair flame
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Yeah

fresh oyster
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yeah

fair flame
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I'm not talking about the Basel problème

fresh oyster
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i need to show to you that both are pi^2/8

fair flame
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Problem*

fresh oyster
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you use the solution in this one

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unless you already accept that the summation is pi^2/8, then i just need to show you the integral

fair flame
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But not the long sum

fresh oyster
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okay

fresh oyster
fair flame
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Oh

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I think I get it

#

Wait

fair flame
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You have 3/4 of π²/6 = π²/8

#

But without using the Basel problem can you do it ?

fair flame
# sleek lake

Because I'm trying to demonstrate the Basel problem with this sum

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So I cannot use the Basel problem

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If I didn't demonstrate it

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I'm trying to

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Forget it

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My question was dumb

fresh oyster
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there are no dumb questions

fair flame
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I think you're wasting your time

fresh oyster
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nah

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its good

#

then you just need to demonstrate the basel problem?

fair flame
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Yeah I think

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With a rigorous demonstration

fresh oyster
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its quite long, but we can do it

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rigorous?

fair flame
fresh oyster
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okay, then we need to get into the analysis

fair flame
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Euler made 2 demonstrations

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I tried to do the second one

fresh oyster
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eulers proofs werent rigorous

fresh oyster
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we have to get into the weierstrass factorization theorem for rigor

fair flame
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Yh

fresh oyster
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are we doing this in the real numbers or the complex numbers?

fair flame
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Complex

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It's more rigorous I think

fresh oyster
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its also much more painful

fair flame
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Ok

fresh oyster
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how much complex analysis do you know?

fair flame
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Let's do it in the real numbers

fresh oyster
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how much real analysis do you know?

fair flame
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What do u mean by analysis

fresh oyster
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uh

fair flame
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Calculus?

fresh oyster
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do you know mathematical logic and set theory?

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yeah, its using that on calculus

fair flame
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Yeah

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I think I know it

fresh oyster
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like you know the operators $\land\lor\neg\iff\implies$

elfin berryBOT
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Cycadellic

fair flame
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Holy

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No

fresh oyster
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i think you just wanted a proof for it

fair flame
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The 2 last I know it

fair flame
fresh oyster
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i dont think you want a rigorous proof for it

fair flame
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And I'm coming back on 5 mind

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Mins

fresh oyster
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The Basel problem is a problem in mathematical analysis with relevance to number theory, concerning an infinite sum of inverse squares. It was first posed by Pietro Mengoli in 1650 and solved by Leonhard Euler in 1734, and read on 5 December 1735 in The Saint Petersburg Academy of Sciences. Since the problem had withstood the attacks of the lead...

fair flame
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Which one is it

fresh oyster
fair flame
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I mean

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Which proof

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There are so many

fresh oyster
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i need to look for it

fair flame
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Which number is us it

fresh oyster
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2

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but it uses big O

fair flame
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Ok

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How do we do now ?

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I explain you what I don't understand?

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Or what

fresh oyster
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go for it

fair flame
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It seems pretty easy tbh

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Short

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Efficient

fresh oyster
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streamline

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cause we already have the sin factorization

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and the mclaurin series

fair flame
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Hmm

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I don't understand the Pk-Pk-1 thing

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On the whole demonstration

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That is the only thing that I don't understand

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We have a multiplication and then an addition

fresh oyster
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step 1 is given

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2 we subtract P_k-1

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3 we bring out the kth term

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4 we factor

fair flame
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Oh yeah I get it

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well, I still don't understand the O(x⁵)

fresh oyster
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O tells us the rate of divergence

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a constant O

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O(2)=O(0)

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says we converge

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but otherwise its just looking at the leading exponent

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O(5x^2+3x+1)=O(5x^2)=O(x^2)

fair flame
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Oh yeah

fresh oyster
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we ignor everything but the exponent

fair flame
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Ok

fresh oyster
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this is mandatory for the wierstrass factorization theorem

fair flame
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But how is it equal

fresh oyster
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O is just looking at what happens eventually

fair flame
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I'm taking about this

fresh oyster
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you could think of it like an abuse in notation

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its technically proper

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but

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when i say x^2-1=O(x^2) its true because O looks towards infinity

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the way we define O, we can say =

fair flame
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O seems to be useless here

fresh oyster
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we just need to show it meets the criteria for converge for the wierstrass theorem

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thats what that step is doing

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this step says: we can use the factorization theorem

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then we use the factorization theorem

fair flame
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Is the O notation mandatory for the demonstration?

fresh oyster
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just in the sense that it says we can use a rule in our demonstration

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its how we can say the euler formula for sine is correct in this case

fair flame
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Ok

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Let's say this is correct

fresh oyster
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wait i got it backwards

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lol!

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sorry

fair flame
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It's so hard to understand

fresh oyster
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its for the telescoping series

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do you know calc 2?

fair flame
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the app ?

fresh oyster
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calculus II

fair flame
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what are u talking about

fresh oyster
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i gues

fair flame
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What's calculus II

fresh oyster
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calculus of integrals and series

fair flame
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oh yeah i think ik it

fresh oyster
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do you know what a telescoping series is?

fair flame
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Normally yes

fresh oyster
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we use that here

fair flame
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How old am I supposed to be to know that ?

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just in case

fresh oyster
fair flame
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Yeah i know this thing

fresh oyster
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you know how you have to look at the cancelling terms?

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hence "telescoping"

fair flame
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yeah

fresh oyster
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the O is just its just saying that after we cancel we have this extra remainder here

fair flame
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ok so it acts like a constant ?

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It's useless

fresh oyster
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rather, its saying it converges

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because x^5 gets big

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its saying that x^5 terms are negligable

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meaning it converges

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does that make sense?

fair flame
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Yeah

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so we don't count it

fresh oyster
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right

fair flame
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But we put it because it exists

fresh oyster
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so it converges

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we put it because we need to demonstrate that it converges in order for the proof to be complete

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we can do the method

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but we still wouldnt know for sure the telescoping works

fair flame
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oh ok

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i get it

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Ok so the value of O(x^5) is really really small

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in front of the other thing

fresh oyster
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right

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at least in the context of infinity

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or rather, towards infinity

fair flame
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yeah

fresh oyster
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also

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this is the riemann zeta function

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ngl

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zeta gets real hard real fast

fresh oyster
fair flame
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The reason why i'm trying to demonstrate it

fresh oyster
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i see

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thats why you wanted complex?

fair flame
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is because tomorrow I want to show the demonstration to my math teacher

fair flame
fresh oyster
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lol

fair flame
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i kind of want to flex

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to show to my teacher that i'm a

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person

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that is interested by math

fresh oyster
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gotta learn the general solution, then you gotta learn the real analytic continuation, then you gotta learn the complex analytic continuation

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we love analytic continuation

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but this stuff really is a headache in complex

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but hey

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if it was easy, there wouldnt be a million dollar problem for it

fair flame
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1 million is too cheap

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i think

fresh oyster
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it is

fair flame
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i would put more

fresh oyster
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there are definitely easier ways to get 1 million

fair flame
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yeah

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and a lot

fresh oyster
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if riemann, dirichlet, and the like couldnt prove it, it def should be more than 1 million

fair flame
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anyways, too complicated for me

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cba to do a rigorous demonstration tbh

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i'm going to make a bad one

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and it's ok

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i'm not even supposed to know that

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i was learning quadratic equations at the beginning of the year

fresh oyster
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you need to make a lot of bad ones to learn to make good ones

fair flame
fresh oyster
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100% will

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ive lost most of my summer breaks from school self-studying

fair flame
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i don't think i'll do it

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How old are u

fresh oyster
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19

fair flame
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ok

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When you were 15-16

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Did u make demonstrations of the basel problem to ur teacher ?

fresh oyster
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probably not basel specifically

fair flame
#

easier or hardr

fresh oyster
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but i was like you 15-16

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trying to learn it to flex

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then i just liked it

fair flame
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which one did u do for example

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if u remember

fresh oyster
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i really liked stoke's theorem around that time

fair flame
#

lemme take a look at it

fresh oyster
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basically: the total spin around the outside is the total spin on the inside

fair flame
#

man i'm so nervous right now

fresh oyster
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still is one of my favorite theorems, honestly

fair flame
fresh oyster
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amazing result

fair flame
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it's so annoying when u don't understand something

fresh oyster
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so, accept the basel problem

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i can show you how to solve this

fair flame
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i know how to solve it with the first method

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but it's a bad method

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so i'm learning the second one

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But with the second one

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I'm not supposed to know the answer of the sum

fresh oyster
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i can show you one really neat trick for this

fair flame
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Show me

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Please

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Wait

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you were demonstrating stoke's theorem to ur math teacher when you had my age ?

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are you crazy ?

fresh oyster
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lol

fair flame
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Tbh i don't understand one line

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of the theorem

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😭

fresh oyster
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stokes'?

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or this summation?

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here is the one really neat trick

fair flame
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you said that u liked stoke's theorem

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I'm talking about stoke

fresh oyster
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on both the summation and the integral, we shorthand the bounds, but actually, they should be x=a, x=b, instead of just a, b

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so we can do this

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oops

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forgot the +1

fair flame
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btw i have a quick question

fresh oyster
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whats up

fair flame
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do u like chess ?

fresh oyster
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i tried to

fair flame
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Are u good at chess ?

fresh oyster
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cant study chess with math

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no

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absolutely not

fair flame
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ok nvm

fresh oyster
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it takes a lot of practice to be good at chess imo

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so, stokes theorem

fair flame
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for me "good" isn't "professional"

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anyways

fair flame
fresh oyster
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this is true in general

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for anything

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with bounds

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summation, integral, product, etc.

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even derivatives

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just because the bounds are =

fair flame
#

Oh

fresh oyster
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this is actually just called u sub for integrals

fair flame
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So it's just a formula

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Right ?

fresh oyster
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that one specifically is summations

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yeah

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but we can apply this thinking on any bounds

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is what i meant

fair flame
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It means f(0)+f(1)+f(2)+...

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?

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Or not

fresh oyster
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they both mean f(1)+f(2)+...

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cause the top sum starts at 1, whereas the bottom sum starts at 0 and does +1

fair flame
#

Oh yeah

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Mb

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Didn't see it

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Alright

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You seem to be a math genius

fresh oyster
#

no

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just spent a lot of time learning

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im not inherently good at it

fair flame
#

I wasted my time

fresh oyster
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just got better with practice

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how so?

fair flame
#

I prefer algebra

fresh oyster
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get very good at algebra

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get like

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very good at that

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very important in math

fair flame
fresh oyster
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lol

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never too late to just start right now/very soon

fair flame
#

Math becomes boring sometimes

fresh oyster
#

yeah

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you gotta find your pace

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hey im blue now

fair flame
#

??

fresh oyster
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apparently, im active

fair flame
#

Oh yeah

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Congrats

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I didn't even see it

fresh oyster
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anyways, keep the balance between the tedious workload and the brilliant proofs

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if you can manage that, you can learn whatever math you want

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just need time

fair flame
#

Yeah

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I get you

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Everything takes time

fresh oyster
#

yeah

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also

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revisit

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if you dont use it, you lose it

fair flame
#

I want to solve Riemann's problem

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Imagine if I solve it

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Omg

fresh oyster
#

thats good spirit

fair flame
#

I believe in you

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I think you can solve it

fresh oyster
fair flame
#

You're too clever

fresh oyster
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i dont think i could

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i dont know the number theory

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its crazy

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ive looked at zeta a little but i cant

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wayy too much

fair flame
#

You, talking to me is like Elon musk talking to a homeless kid

fresh oyster
#

i mean, it is true anyways, it works for the first 10^80 zeroes

fair flame
#

Like Syracuse conjecture

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Why am I talking about it

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Idk man

fresh oyster
#

free up this channel, yk?

fair flame
#

Yeah I think I'll stop it here

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Too much math for today

#

.close

marsh citrusBOT
#
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marsh citrusBOT
#
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velvet violet
#

can I get some help please?

marsh citrusBOT
still temple
#

so p(a) = -3

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where p(x) = x^2 + ax^2 + 3x -5

still temple
#

If the binomial in question is x-a then the a we're talking about is the 2 from x-2

velvet violet
still temple
#

So wouldn't it be p(2)=-3 where p(x)=x^3+ax^2+3x-5?

still temple
#

i should've used another variable but yeah

velvet violet
still temple
#

anyway the overarching point is to use that principle

marsh citrusBOT
#

@velvet violet Has your question been resolved?

velvet violet
#

I assume I use the same principal of the remainder theorem right?

marsh citrusBOT
#
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velvet violet
#

.reopen

marsh citrusBOT
#

marsh citrusBOT
#

@velvet violet Has your question been resolved?

modest pulsar
#

factor theorem is your friend

marsh citrusBOT
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lost hound
marsh citrusBOT
lost hound
#

Help

marsh citrusBOT
#

@lost hound Has your question been resolved?

lost hound
#

<@&286206848099549185>

#

.close

marsh citrusBOT
#
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solemn plover
#

having a bit of trouble over here

marsh citrusBOT
solemn plover
#

its about logarithmic equations

hardy girder
#

Show the question

solemn plover
#

i dont have he question wih me b

random palm
#

nice

#

how do we help you then?

solemn plover
#

suppose i have (ln(a))/c

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how can i write this expression in terms of only 1 ln function

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in other words simpliify it

late geode
#

its already simplified

solemn plover
#

nothing more yes?

#

thanks

cobalt sentinel
#

another way of writing it:

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Doesn’t necessarily simplify it tho

elfin berryBOT
#

Stephen

marsh citrusBOT
#

@solemn plover Has your question been resolved?

marsh citrusBOT
#
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still temple
marsh citrusBOT
still temple
#

whats that thing called where you put the limit inside the function e^lim...?

#

i feel like thats what i need to do here right?

devout mauve
#

continuity of e^x?

marsh citrusBOT
#

@still temple Has your question been resolved?

marsh citrusBOT
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vale yacht
#

Just looked at it.
In the 6 >= 2t^2 - t
He moved it so it was
0 >= 2t^2-t-6
I moved it so it was
6-t-2t^2>=0

vale yacht
#

Aka the difference is >= or <=

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now based of what does it change? or what can I do

#

I didn't multiply by - so why is that error occuring?

marsh citrusBOT
#

@vale yacht Has your question been resolved?

vale yacht
#

<@&286206848099549185>

tardy bridge
#

@vale yacht I'm confused by your inequality manipulation, you should have -2t^2+t+6>=0

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then multiply by -1 so 2t^2-t-6<=0
solve by factoring or quadratic formula

vale yacht
#

but why is the multply by -1 a must in what you said?

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is it because the a is negative and I need to account for it?

tardy bridge
#

yes

vale yacht
#

like I get what you mean

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but not 100% sure why it's needed

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can you explain?

tardy bridge
#

if you use quadratic formula it's not needed
but you said you got the inequality 6-t-2t^2>=0

#

this is impossible, a and b always have opposite signs

vale yacht
#

Nevermind, forgot to change the - of the t to a positive when switching sides

#

I thought I missed something and looked but didn't quite catch that

#

Yeah no I get it now. thanks

#

.close

tardy bridge
#

okay great!

marsh citrusBOT
#
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marsh citrusBOT
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serene kestrel
#

May I ask how to get the corresponding angles and corresponding side??

serene kestrel
#

im stuck in in number 3 and 5

#

<@&286206848099549185>

paper raptor
#

As for sides, repeat the same exercise but find which sides correlate

marsh citrusBOT
#

@serene kestrel Has your question been resolved?

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gritty sequoia
#

the limit as n goes to infinity of 3^n+2^n/3^n+1 + 2^n+1 = 1/3 , how?

gritty sequoia
#

i know that 3^n/3^n+1 = 1/3 and 2^n/2^n+1=1/2 but why is the final answer 1/3

static quarry
#

please use brackets to disambiguate, do you mean: $$\frac{3^n + 2^n}{3^{n+1} + 2^{n+1}}$$

elfin berryBOT
gritty sequoia
#

thats correct

static quarry
#

cool

#

nonrigorous intuitive explanation: 3^n grows much faster than 2^n, so for very large n, the num is dominated by 3^n and the denom is dominated by 3^(n+1)

#

so the fraction looks like 3^n / 3^(n+1) = 1/3

#

so that gives you some feel for why it should be true, now you need to make it more rigorous..

#

for that, try dividing the num and denom by 3^n

gritty sequoia
#

hm alr

#

ill work on more practice problems

#

ty

static quarry
#

sure, gl

marsh citrusBOT
#

@gritty sequoia Has your question been resolved?

#
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still temple
#

Hey

marsh citrusBOT
still temple
#

The question asks state the principal angle

#

How would I find it

#

-42/15

sleek lake
#

you add 2pi to it until it's positive

jovial star
#

it also needs to be less then pi/2

sleek lake
#

unless it's in degrees?

#

wait really?

#

i think that would be called reference angle

still temple
#

@sleek lake Wait, but it’s only in radians we don’t use degrees

#

Generally it’s radians only

sleek lake
#

sure

still temple
#

Why do you minus 2 pi tho

sleek lake
#

you plus

still temple
#

How come?

#

Can you explain why?

#

Is it because the principal angle can only be positive?

#

Or am I incorrect

sleek lake
#

no sorry

#

yes it's because it can only be positive

jovial star
sleek lake
#

that's valuable info

still temple
#

What would the final answer be

#

I assume it cannot be negative ever

marsh citrusBOT
#

@still temple Has your question been resolved?

sleek lake
#

the final answer is 2pi − 42/15

still temple
#

@sleek lake

sleek lake
#

it would be mine

#

idk what's wrong

still temple
#

I don’t think that’s wrong, but you have to solve for it

#

@sleek lake what do you get when solving

sleek lake
#

i can't solve it

#

it would be like solving pi − 1

#

you can't

still temple
#

It says the answer is 18 pi over 35

sleek lake
#

oh you;re right i didn't notice it's not simplified

still temple
#

How do we even get this

sleek lake
#

42/15 = 14/5

still temple
#

How?

sleek lake
#

dude what

still temple
#

How did they get the answer as that

#

Can you explain

sleek lake
#

not yet

still temple
#

Huh

sleek lake
#

18pi over 35 is a different number even

#

i give up

still temple
#

Show your work…. @sleek lake

sleek lake
#

,calc (2pi - 42/15)

elfin berryBOT
#

Result:

3.4831853071796
sleek lake
#

,calc (18pi /35)

elfin berryBOT
#

Result:

1.6156762218462
sleek lake
#

my work

still temple
#

2pi-42/15 is 18pi/35? @sleek lake

sleek lake
#

no

still temple
#

Oh okay

#

So what do we get when we minus 2pi-42pi/15?

sleek lake
#

why do that?

still temple
sleek lake
#

you can do it too it should work for you

#

,calc

elfin berryBOT
#

Please give me something to evaluate.
See ,help calc for usage details.

still temple
#

,calc (2𝞹-42𝞹/15)

elfin berryBOT
#

The following error occured while calculating:
Error: Undefined symbol 𝞹

still temple
#

,calc (2pi-42pi/15)

elfin berryBOT
#

Result:

-2.5132741228718
still temple
#

^

sleek lake
#

what's interesting about it?

#

what do you mean lol

still temple
#

You asked me to do this calculation !!!

sleek lake
#

you suggest we do −42pi/15 instead?
okay

#

you asked me first

still temple
#

Bro we cannot do a negative

#

The principal angle cannot be negative

sleek lake
#

my angles is positive

still temple
#

Yeah, but what is that in radians

#

Obviously you minus 360

sleek lake
#

you're not making sense

still temple
#

Bro 2 pi is 360 in degrees

#

You have to minus the 2 in the same symbol

#

You can’t minus degrees and radians together

sleek lake
#

you're talking about something completely new

still temple
sleek lake
#

well i can't keep up

still temple
#

2 pi is 360 degrees

#

It’s one full rotation

sleek lake
#

i gave up
then you asked what's 2pi-42pi/15

still temple
#

Yeah

sleek lake
#

that went nowhere now you're saying we're in degrees

#

i can't keep up

still temple
#

It’s basically the same thing as 360-42pi/15

sleek lake
#

why do anything with 42pi/15 at all

#

what is it, how ddid you get it

still temple
#

Apparently you add 30pi over 15

sleek lake
#

that would be my answer

#

that's good, but you already said it's wrong

still temple
#

…..

#

🤦‍♂️

sleek lake
#

showing my work, i liked that part

#

,calc (30pi/15 - 42/15)

elfin berryBOT
#

Result:

3.4831853071796
sleek lake
#

,calc (18pi /35)

elfin berryBOT
#

Result:

1.6156762218462
still temple
#

You add it

sleek lake
#

i do

still temple
#

yeah

sleek lake
#

yeah

still temple
#

Why do we do that

sleek lake
#

to force it to be positive?

still temple
#

Why do we add 30pi over 15

sleek lake
#

i can't explain the why

#

you can add 30pi /15 to angles

#

they stay the same

still temple
#

Or is it because you don’t know ……?

#

What……

#

That doesn’t even make any sense bro….

sleek lake
#

i indeed don't know why angles stay the same when you add a full turn

still temple
#

Okay then don’t help

sleek lake
#

okay

still temple
#

We should wait for someone that knows how to do the question

#

To show us how to do it

#

Ok @surreal hull

sleek lake
#

go ahead

still temple
#

Bro wtf

#

Is wrong with you guys

#

You guys join to waste time

#

I’m going to bed

#

You guys are wasting my time

#

Not you since you tried @sleek lake you’re good

marsh citrusBOT
#

@still temple Has your question been resolved?

marsh citrusBOT
#
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pale tiger
#

oof

pale tiger
# still temple Why do we add 30pi over 15

30pi/15 simplifies to 2pi, so it's adding a full rotation

imagine if you walked 360 degrees around a pole, you'd end up at the same spot. that's what frownyfrog was trying to say

marsh citrusBOT
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sage gale
#

,,\lim_{x\to0}\frac{sin x}{x} = 1

marsh citrusBOT
elfin berryBOT
sage gale
#

can someone help me show this without fancy methods

#

as in, geometrically

#

wait ill just look it up

#

.close

marsh citrusBOT
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errant lance
#

need help , Im stuck

marsh citrusBOT
bitter dawn
#

Sin can't be bigger than one

errant lance
#

oh. thanks 😭

bitter dawn
#

And you can use the formula for sine

marsh citrusBOT
#

@errant lance Has your question been resolved?

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opaque wolf
#

bye

#

@still temple your channel is going to close please open a new one

still temple
#

k

marsh citrusBOT
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cunning tartan
#

x^2+y^2-6x-14y+42=0 have a quick question is the discriminant -4?

marsh citrusBOT
#

@cunning tartan Has your question been resolved?

oblique karma
#

Not sure if circle functions are meant to have discriminant?

#

It should only apply to quadratic expressions

#

Ahh yeah I wouldn't know

tulip shale
#

I believe a discriminant is only related to quadratic equations

#

The discriminant determines how many real zeros the quadratic equation has

#

Oh I am wrong the discriminant determines the type of conic section

#

So what you do is find b^2 - 4ac and if it is < 0 and a = c then it is a circle

#

Rewrite the equation in general form:
Ax^2 + Bxy + Cy^2 + Dx + Ey + F
In this case there is no xy so B = 0 and A = 1 and C = 1

cunning tartan
#

hm yea the homework asked for a discriminant

#

So Idk

tulip shale
#

0^2 - 4(1)(1) = -4 so yes the discriminant is -4

cunning tartan
#

yea that’s what I calculated aswell so I’m right thanks

tulip shale
#

So then since the discriminant is < 0 and B = 0 it is a circle

cunning tartan
#

mm yea

#

thank u

#

👍

#

.close

marsh citrusBOT
#
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left plaza
#

Vectors are getting me confused, I need someone to lighten it up for me.

left plaza
#

Translation for #3:

#

Make an equation for the smallest vector using the difference or the addition of other vectors

#

For A it's just u - v = w

#

But b can it go like.
CA - CB = AB

marsh citrusBOT
#

@left plaza Has your question been resolved?

marsh citrusBOT
#

@left plaza Has your question been resolved?

marsh citrusBOT
#

@left plaza Has your question been resolved?

left plaza
#

.close

marsh citrusBOT
#
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hard schooner
#

hi
we know sinx ~ x (and the rest of the maclaurin series)

  1. This is correct at x=0 or any x?
  2. Can we say sinax~ ax?
woeful phoenix
#

1.if x approaches 0
2. If x approaches 0

hard schooner
#

ty

#

.close

marsh citrusBOT
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severe briar
#

idk how to do part B or if there's a better way to do part A

shrewd grotto
#

Can someone help me with this pls

marsh citrusBOT
#

@severe briar Has your question been resolved?

severe briar
#

😭

marsh citrusBOT
#

@severe briar Has your question been resolved?

severe briar
#

.close

marsh citrusBOT
#
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severe briar
#

.reopen

marsh citrusBOT
#

blazing gazelle
#

@severe briar about the part B you follow the same steps, you try to find θ

severe briar
#

the same steps?

#

im not entirely sure

blazing gazelle
#

@severe briar oh sorry i saw wrong

#

you use the half angle formula

severe briar
#

how

blazing gazelle
#

sin(θ/2) =± √((1-cosθ)/2)

severe briar
#

like ik the formula

#

but what would cos be

blazing gazelle
#

(cosθ)^2+(sinθ)^2=1

#

you find cos from here

severe briar
#

ommmgg

#

i did not think of that in all this time

#

yes

blazing gazelle
#

dont worry my friend

severe briar
#

i got around .72

#

,w sqrt(1-(2sqrt(3)/5)^2)

severe briar
#

is that right

#

@blazing gazelle

blazing gazelle
#

is that the sin(θ/2) value?

#

wait

severe briar
#

thats the cos

severe briar
#

cos = sqrt(1-sin^2)

#

sin = 2*(sqrt(3)/5)

blazing gazelle
#

its right

#

i calculate

#

that θ is 0.765

#

so the cos is something like 0.72

severe briar
#

why is it sqrt(13)/5 instead of sqrt(12)/5

blazing gazelle
#

listen you can do the other thing

#

go to a calculator

severe briar
#

and?

blazing gazelle
#

calcute θ from the sin

#

and then calculate the cos

#

just to see if its right nothing else

severe briar
#

,w cos(arcsin(2sqrt(3)/5))

blazing gazelle
#

you found the cos thats right

#

its 0.7211

#

actually is

#

what is the problem? i cant see it

severe briar
#

its probably right

blazing gazelle
#

yes it is

severe briar
#

w, sqrt((1-sqrt(13)/5)/2)

#

,w w, sqrt((1-sqrt(13)/5)/2)

severe briar
#

rip

#

,w sqrt((1-sqrt(13)/5)/2)

severe briar
#

is that accurate

blazing gazelle
#

cos is 0.37?

severe briar
#

i think its right

#

i need to do this next

blazing gazelle
#

its right

#

cause

#

θ=43.85377861

severe briar
blazing gazelle
#

are you studying engineering?

severe briar
#

im not its just a math class with applications

#

but id love to know more

blazing gazelle
#

for school?

severe briar
#

yep

#

but yea idk how to do that problem

severe briar
marsh peak
# severe briar

f(theta) is defined as the difference in length of the spring from its non-compressed length and in part A they are asking you to find all theta such that the spring's length is equal to its non-compressed length

#

So you simply need to solve f(theta) = 0

#

Part B is the same except you solve f(2theta) = 0

severe briar
#

oh the way they worded it made no sense

marsh peak
#

And part C is just solving f(theta) = g(theta) (for that you may want to rewrite 1 - cos^2 as sin^2)

severe briar
#

so theta = pi/4 or 3pi/4

#

for a

marsh peak
#

Isn't it sin(theta) = -sqrt(2)/2 though?

severe briar
#

oops

#

so 5 and 7 pi over 4

marsh peak
#

Yes

severe briar
#

i made sin(2theta) that explains what i was doing wrong lol

marsh peak
#

Yes

#

Yea you are supposed to set 2sin(2theta) + sqrt(2) equal to zero

severe briar
#

yeah that makes sense i still have the same issue then

#

like i get

#

sinx*cosx = -sqrt(2)/4

#

how can i simplify this

marsh peak
#

Why would you expand though, just solve for 2theta in sin(2theta) equal to -sqrt(2)/2

#

-> 2theta is either 5pi/4 or 7pi/4

severe briar
#

oh rightr

#

5pi/8 or 7pi/8

marsh peak
#

Yes

#

Hm there may be a third solution though

#

I think 13pi/8 also works

severe briar
#

wait im confused

#

,w sin(5pi/8)

severe briar
#

,w sin(7pi/8)

marsh peak
#

Double it catThink

#

,w sin(2*5pi/8)

elfin berryBOT
severe briar
#

confusion 100

marsh peak
#

5pi/8 makes sin(2theta) turn into -sqrt(2)/2

#

Not sin(theta)

severe briar
#

oh right

marsh peak
#

,w solve sin(2x) = -sqrt(2)/2 for x in [0, 2pi)

#

4 sols

#

Yup, guessed it

#

So, basically, since 0 < theta < 2pi

severe briar
#

i never knew wolfram alpha could do that omg ;-;

marsh peak
#

It means that 0 < 2theta < 4pi

#

So we have to solve for 2theta in sin(2theta) = -sqrt(2)/2 in [0, 4pi)

#

Which yields four solution

marsh peak
elfin berryBOT
marsh peak
#

thonk Okay clicking "more" didn't do much in this case

severe briar
#

XD

#

do you have pro version?

marsh peak
#

No

#

You can use it on the server as well

severe briar
#

oh right

#

wait can you make it show steps thru the server?

marsh peak
#

Not sure

#

,w solve t^2 + t - 6 = 0

elfin berryBOT
marsh peak
#

Yeah no

severe briar
#

lol i ended up with this for part c

#

could i like complete the square or something trigonometrically

#

is that possible

#

should i do something else

marsh peak
#

Meaning sin(x) = 0 or sin(x) - 2 = 0

#

But note that sin(x) - 2 can never be 0

severe briar
#

oh yeah thats better

#

so x=0 + 2pi

#

or x=pi +2pi

marsh peak
#

I think they want x to be in [0, 2pi) per usual

#

So x = 0, pi or 2pi

severe briar
#

they actually didnt specifiy this time

#

in part a they said determine all values

#

here it says determine what times

#

ok i think ill turn it in

#

everything seems right

marsh peak
#

Yeah

severe briar
#

ok now i have a bunch of vector questions

severe briar
marsh peak
severe briar
#

<-4-4,-1-3>

#

<-8,-4>

#

right?

#

sqrt(64+16)?

marsh peak
#

Yeah

severe briar
#

and the most obvious angle is in the third quadrant

#

so theta = 206

#

i dont think i would be able to calculate the angle right?

#

idk how i would do that

marsh peak
#

You don't need to calculate but it would be 180 + arctan(4/8)

severe briar
#

oh ok

#

ok cool that gets me the angle

#

is it always plus 180 or does it depend

marsh peak
#

Depends

#

If v was, let's say, <3, 4>, then the angle would be just arctan(4/3)

severe briar
#

oh so like on the quadrant?

#

so which quadrants require you to add and how much

marsh peak
#

In 2nd you add 90
In 3rd you add 180
In 4th you add 270

severe briar
#

i think this is accurate

marsh peak
#

And btw it switches between y/x and x/y from quadrant to quadrant

severe briar
#

wait isnt adding 360 full circle?

#

oh right ok

marsh peak
#

Yeah I meant 270 there

severe briar
marsh peak
elfin berryBOT
marsh peak
#

,w pi + arctan(19/9) radians into degrees

elfin berryBOT
marsh peak
severe briar
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rip

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XD

marsh peak
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,w (pi + arctan(19/9))* (180/pi)

elfin berryBOT
severe briar
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i think all these are right just making sure

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my best guess just by looking here is o

marsh peak
elfin berryBOT
marsh peak
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,w (pi/2 + arctan(16/6)) * (180/pi)

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Weird

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Oh did I type in wrong order

elfin berryBOT
marsh peak
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Yeah

marsh peak
marsh peak
severe briar
severe briar
severe briar
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thats alr its only one question

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now over to forms

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which goes first im guessing x then y

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so b?

marsh peak
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Yes

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<a, b> = ai + bj

severe briar
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so based on that this should be right as well?

marsh peak
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Yes

severe briar
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trigonometric form the cos is x and sin is y right

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how do you find the values though just find the angles?

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and whats the number in front

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theres probably a formula actually lemme find it

marsh peak
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The number in front is the magnitude

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Let's see

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,w (pi/2 + arctan(15/8)) * (180/pi)

elfin berryBOT
marsh peak
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Yeah it's a