#help-23

1 messages · Page 354 of 1

hard crest
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the other point is this blue point here

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remember, this was the spot where the parabola was widest

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what is the blue point?

drowsy slate
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x intercept?

hard crest
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yes, it is

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but what is it numerically?

drowsy slate
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9.8?

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or 4.9?

hard crest
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are you familiar with the form of (x, y) for writing a point?

drowsy slate
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yes yes

hard crest
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okay

drowsy slate
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im srry for not using it

hard crest
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what is the blue point, in that notation?

drowsy slate
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(4.9,0)

hard crest
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perfect

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okay, so since the parabola goes through that point, if we plug that point into our parabola equation then it must be true

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so we can use that to solve for a

drowsy slate
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this is like the easist math on here i was going through all the servers

hard crest
#

here's our parabola equation again
$y = ax^2 + 9.8$

flat frigateBOT
hard crest
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and we can plug in x = 4.9 and y = 0 to that

drowsy slate
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ok

hard crest
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and solve for a. Can you do that?

drowsy slate
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yes wait

hard crest
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sure

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it'll take some arithmetic

drowsy slate
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mhm

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a=0.41

hard crest
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,calc 9.8 / (4.9^2)

flat frigateBOT
#

Result:

0.40816326530612
hard crest
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kinda feel like you might have a sign error though

drowsy slate
#

wdym

hard crest
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0 = a(4.9)^2 + 9.8
-9.8 = 24.01a
-0.41 = a

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also, the parabola is concave down so we know the x^2 coefficient should be negative

drowsy slate
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ohhhh k

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wait ima js come

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js continue solving

hard crest
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we should be just about done here. let's put that value of a back into our parabola equation

hard crest
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you appear to have lost an h

drowsy slate
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ahh shi-

hard crest
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y = -0.41x^2 + 9.8

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the funny thing here is that we started with vertex form but this is also standard form

drowsy slate
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ohhh yaaaaaa

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thats so smart

hard crest
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(that's because it's symmetric around the y axis. if it wasn't, you'd have to expand a square. not a big deal)

drowsy slate
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hmm

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thank you so much

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ill do it from here now

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:finish

hard crest
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.close

safe radishBOT
#
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drowsy slate
#

.close

safe radishBOT
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frozen comet
#

hi, im a little confused on what it means when im finding the area under the curve.. i have the points for m and n, i know i need to find the integrals with the limits of the x points for both but i dont understand how it works. to put it simply, i know how to get the answer but i want to understand why it works so i can remember it.

frozen comet
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i dont understand how yellow-blue= the grey

prisma wren
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Cause you misdrew blue

frozen comet
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where is it supposed to be?

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ohhh

prisma wren
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blue is the area UNDER the parabola

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the intergral is always the area under a curve, never above

frozen comet
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like this?

prisma wren
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yep

frozen comet
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makes so much more sense

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lol i knew it was something simple i wasnt getting

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thanks a million

#

.close

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smoky whale
safe radishBOT
stoic saddle
#

!status

safe radishBOT
#
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
stoic saddle
#

also the epi is just extra

fierce nimbus
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you should go ahead and send it

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your answer and your steps, too

smoky whale
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i got 50

smoky whale
fierce nimbus
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atleast from my solving

granite pollen
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i got 50 aswell

fierce nimbus
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oh wait sorry pemdas lol

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no u are right

smoky whale
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alright im gonna close then

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or do i need to send explaination

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.close

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steep magnet
safe radishBOT
steep magnet
#

I need to find the limit with hopitals or whatever its called

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derivative of numerator is sin(x)

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derivative of denom is 2x

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sin(x)/2x

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sin(0)/2(0)

languid ermine
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dont forget your limit

near atlas
steep magnet
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Can I apply infinitely times?

languid ermine
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yes

steep magnet
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Alright I see

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Thanks!

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❤️

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.close

languid ermine
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as many times as needed c:

safe radishBOT
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near atlas
loud wren
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but this is me being technical haha

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Don’t worry about it, spamming L’H is completely fine in an informal context

restive niche
#

what you mean is you can apply it in 0/0 or inf/inf forms only

near atlas
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quasi zodiac
#

I want to rearrange this table in a way that all 6 columns add up to 36 and all rows add up to 18 (they already do)

1 2 4 3 5 3
2 1 4 3 5 3
1 4 2 3 5 3
1 2 5 3 4 3
2 1 5 3 4 3
1 2 5 3 4 3
1 4 5 3 2 3
4 1 5 3 2 3
1 5 4 3 2 3
2 4 5 3 1 3
4 2 5 3 1 3
2 5 4 3 1 3

you can rearrange by shifting, flipping or both
-example of rotating 1 2 4 3 5 3 (first row) becomes 5 3 1 2 4 3 (shifted 2 to the right)
-example of flipping 1 2 4 3 5 3 (first row) becomes 3 5 3 4 2 1 (flipped)
-example of both 1 2 4 3 5 3 (first row) becomes 4 2 1 3 5 3 (flipped (into 3 5 3 4 2 1) then shifted 2 to the right)

PD: all these 12 rows are different from each other no matter how much you flip or shift them, so they are always unique

a maybe possible tactic would be to make it so each column contains two 1s, two 2s, four 3s, two 4s and two 5s, since each row already contains half that amount of each number so it balances out on it's own

desert juniper
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!original

safe radishBOT
#

Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.

#

@quasi zodiac Has your question been resolved?

quasi zodiac
quasi zodiac
# desert juniper !original

Its thecnically an original question

This was my first request, but since it was declared impossible by some sources, i wanted extended the search into more

the principal idea was to get a 12 by 6 table that contained any numbers as long as all 12 were different no matter how much you flip or rotate them.

it seemed too tight or impossible on the original post so i made it more flexible with these values

If it is impossible too, i would like to know the solution with the lowest possible numbers

safe radishBOT
#

@quasi zodiac Has your question been resolved?

tardy mango
safe radishBOT
#

If you are done with this channel, please mark your problem as solved by typing .close

safe radishBOT
#

@quasi zodiac Has your question been resolved?

quasi zodiac
#

well that specific table is impossible, noticed something in the pattern.
its impossible to evenly distribute the 3s that way since they will bunch up eventually in the table

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.close

safe radishBOT
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fresh gate
#

Hey guys so this is a piece of text from Boyd Convex Optimization. So I'm trying to understand/prove the statement given here but I'm not able to do so. Can someone help? GPT is giving garbage too or maybe correct me if I'm wrong.

fresh gate
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<@&286206848099549185>

safe radishBOT
#

@fresh gate Has your question been resolved?

safe radishBOT
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@fresh gate Has your question been resolved?

safe radishBOT
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@fresh gate Has your question been resolved?

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frozen quarry
#

Is i) a function?

safe radishBOT
plucky elk
#

Most quadratics in y are not functions

frozen quarry
#

What subject isn’t making it a function?

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@plucky elk

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<@&286206848099549185>

plucky elk
frozen quarry
#

how do you simplify this?

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mutiply by y both sides?

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(to get rid of y fraction)

safe radishBOT
#

@frozen quarry Has your question been resolved?

frozen quarry
#

can anyone fuckinng help me?

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.close

safe radishBOT
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potent cradle
#

@frozen quarry

#

u stilll need help?

frozen quarry
safe radishBOT
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ornate pike
#

cevap

safe radishBOT
ornate pike
#

31

quick crater
#

?

quasi timber
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@ornate pike do you have a question?

ornate pike
#

no

quasi timber
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alright then

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.close please

hollow heart
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can u help me plaease

safe radishBOT
ornate pike
#

.close

safe radishBOT
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quick crater
#

(or any channel in the "available" section)

safe radishBOT
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crude storm
#

I'm working on getting the slope of the derivative of cos(xy)=y-1 at (pi/2, 1)
My process is as follows

-sin(xy)((x)'(y)+x(y)')=dy/dx+❌ then further derive terms to
-sin(xy)(y+(dy/dx))=dy/dx then distributive property for
-ysin(xy)-(dy/dx)(sin(xy))=dy/dx then get the derivative slopes on the same side for
-ysin(xy)=(dy/dx)+(dy/dx)sin(xy) then backwards distributive property for
-ysin(xy)=(dy/dx)(1+sin(xy))
so my final equation is (-ysin(xy)/(1+sin(xy))

Plugging in these coordinates, all the sins and the individual y become 1's, leading to an answer of -1/2 but that's not a given answer.
What am I doing wrong?

safe radishBOT
#

@crude storm Has your question been resolved?

crude storm
#

<@&286206848099549185>

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I think it's been 15 minutes at least

vapid scarab
#

so the second derivative?

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also is this a parametric function or just a function in two variables

crude storm
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wdym 1st vs second derivative and what does parametric function mean?

vapid scarab
vapid scarab
crude storm
vapid scarab
#

do you know partial derivatives?

crude storm
#

partial?

vapid scarab
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yes, they kinda make it easier

crude storm
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how does one reach a partial derivative?

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is it just changing gears partway through?

vapid scarab
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its by ignoring all variables and considering them as constants that you are NOT differentiating wrt

crude storm
vapid scarab
#

hmm okay, tho it does make things easier

vapid scarab
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at the second line

crude storm
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the second line?

vapid scarab
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you miss an x

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x(y') becomes dy/dx

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which is why you get an incorrect expresseion

vapid scarab
crude storm
#

ok

vapid scarab
crude storm
#

lemme evaluate a fixed vesrion

#

this works ty

#

.close

safe radishBOT
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safe radishBOT
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exotic charm
#

can i get a hint for part c showing completeness

exotic charm
#

ik i have to show cauchy implies convergent but im still stuck

safe radishBOT
#

@exotic charm Has your question been resolved?

safe radishBOT
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@exotic charm Has your question been resolved?

safe radishBOT
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@exotic charm Has your question been resolved?

safe radishBOT
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pseudo beacon
#

Let $m>1$ be an integer and $a$, $b$, $c$ be three
complex numbers such that $a+b+c=0$ and $a^m+b^m+c^m=0$.
Prove that two of $a$, $b$, $c$ have the same magnitude.

flat frigateBOT
pseudo beacon
#

I am stuck since i feel like all the information i found is useless and wont lead to a solution

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i have tested stuff like newtons sums or geometric interpretations of the problem

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See that $ab+bc+ac=0$ means that they are cube roots of unity so we can just let $ab+bc+ac=1$. Then just call $p(n)=a^n+b^n+c^n$. let $k=abc$. Then if we just calculate the first few numbers we with the recursion $p(n+3)=xp(n)-p(n+1)$ obtained from $(y-a)(y-b)(y-c)=y^3+y-x$ having roots $a,b,c$\
$p(0)=3, p(1)=0, p(2)=-2, p(3)=3x, p(4)=2, p(5)=-5x, p(6)=3x^2-2...$ didnt feel like writing out but we can observe that when $n=3m$ the leading term would be $3x^m$. Then if $n=3m+1$ the leading term would be $\frac{m(3m+1)k^{m-1}}{2},$ and for $n=3m+2, -(3m+2)k^m$

flat frigateBOT
pseudo beacon
#

just some stuff i wrote out near the end can be done by a very simple induction

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i feel like the polynomials that are created in the recursion only have real roots, (what i have seen writing more of them out) and that would finish the problem since a^2+b^2+c^2=-2 would follow which must have two of the same magnitude

safe radishBOT
#

@pseudo beacon Has your question been resolved?

pseudo beacon
#

<@&286206848099549185>

safe radishBOT
#

@pseudo beacon Has your question been resolved?

split kayak
#

okay, using euler's

flat frigateBOT
split kayak
#

Given how we represent Complex Numbers in the form of (a,b) over a Cartesian Plane, we can also associate all these as if they were vectors.

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From that point of view:

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Imagine you set an arbitrary vector at some random angle (we will use our coordinates with respect to this vector)

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We know two things, the vertical of the two other vectors has to add up to the opposite of V1, and their horizontals has to cancel out.

errant rapids
#

Oh is this just similar triangles

split kayak
errant rapids
#

yea but i see where you're going

#

well maybe but keep going

split kayak
#

This also sets an axis of "simetry", both vectors can be to the left or right of v1, cause if not, they horizontals wont cancel.

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From here we got these two cases

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Now, what does happen when we do z^m?

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One. 1 Unless r = 1, the modulus changes
2. the vectors rotate

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given:
$z^m= \left(re^{\theta i}\right)^m = r^m e^{\theta\cdot m i}$

flat frigateBOT
split kayak
#

The first one is clearly possible, fun enough, doing ^m keeps simetry over a different set of axis rotated around 90 degrees
We have to show that the second one isnt possible to keep the balance in

pseudo beacon
#

Yo i dont think this is getting anywhere

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I know vectors in this context but i just dont think this representation would be particularly useful in writing the proof

split kayak
#

You can most probably translate it down to the eulers notation

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Which, tbh, i was already checking

pseudo beacon
#

Ive thought of a method for continuing my approach

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But like its kind of weird

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Its comparing the between every third polynomial in terms of x and seeing how the roots they have alternate which polynomial it comes from

split kayak
#

if i have to give some input, the polar form idea is arguably the easiest

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You can solve for when a is strictly in the negative imaginary axis and then argue for similarity under rotational simetry

pseudo beacon
#

No

split kayak
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why not

pseudo beacon
#

Similarity would not work

split kayak
#

Okay, clarification, ">why you think it wouldnt work"

#

if $a+b+c = 0$, then
$(a+b+c)\cdot i^{\alpha}$ = 0

flat frigateBOT
split kayak
#

and multiplication by some power of i defines rotation in the complex

pseudo beacon
#

Ok the whole figure isnt rotated the same angle

split kayak
#

i know it doesnt.

#

I mean, solve for when a = -ri

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instead of solving for all a

pseudo beacon
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I know what you are saying

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This would not be an easy solve this would not simplify the problem still

split kayak
pseudo beacon
#

No bruh

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This would not be such a simple solution there are many cases you have to account for with this approach

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Having this simple representation isnt any real progress

#

Ive tried that

#

The problem is from ELMO shortlist a8

pseudo beacon
split kayak
#

goddam i was writing with pen and my app crashed, ill text it, lmao

safe radishBOT
#

@pseudo beacon Has your question been resolved?

safe radishBOT
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thin lion
safe radishBOT
thin lion
#

is part a correct?

hasty monolith
#

No it’s not sorry

thin lion
#

wait yea I forgot I need to define F and P also

hasty monolith
#

Yeah

thin lion
#

alright hold on

hasty monolith
#

What app are you using

thin lion
thin lion
#

I’m a bit confused on the sample space

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Cause I initially assume it was just {H,T}

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Since those are the only 2 outcomes

#

wait I get it

#

.close

safe radishBOT
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safe radishBOT
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mortal thicket
#

how do i solve

safe radishBOT
mortal thicket
#

ik how to solve second order linear inhomogenous using associated quadratic and so on

vagrant ice
#

there's a homogenous solution whose characteristic equation is $r^3 + 4r = 0$

flat frigateBOT
mortal thicket
#

so my roots are 0 and +/- 2i

vagrant ice
#

and then you would guess $y_p = ax^5 + bx^4 + cx^3 + dx^2 + ex + f$ for the particular solution

flat frigateBOT
mortal thicket
#

what do i do with my roots

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for second order i just memorise what to sub them in to depending on what i got

mortal thicket
vagrant ice
flat frigateBOT
vagrant ice
#

so you need a polynomial with that degree

vagrant ice
mortal thicket
#

i was taught to just take that degree

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for second order

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if the right has an x^2 poly, i should just take ax^2 + bx + c

vagrant ice
mortal thicket
vagrant ice
#

yeah you actually just guess a cubic, my bad

well, this is also a repeated case where you have e^0 = constant coming from the homogeneous solution

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so that's why you don't guess a quadratic here

mortal thicket
vagrant ice
#

you have to go one power up

vagrant ice
mortal thicket
#

and for my homogenous soluion

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do i get $c_1 e^{2ix} + c_2 e^{-2ix} + c_3e^{0}$

flat frigateBOT
#

Big Chicken

vagrant ice
#

(usually we use cos(2x) and sin(2x) but this is fine)

vagrant ice
flat frigateBOT
mortal thicket
#

ok yeah

split kayak
#

Quick question, is this asking for a solution or the general one.

mortal thicket
#

general

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so for my homogenous

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can i leave it in that form

#

do i haev to simply it into the harmonic form>

vagrant ice
#

yes, cause it's the general solution

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oh it depends on what your TA wants

split kayak
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if it asks for A solution

#

then this is pretty basic stuff

#

like, you can recur to the derivative of polynomials

mortal thicket
#

do i just supply the inhomogenous part

split kayak
#

A solution means at least 1,

#

usually DEs have infinite > which would require the general solution

mortal thicket
#

right so how do i give one

split kayak
#

For exactly one, the whole process is much simpler tbh

mortal thicket
#

how so

split kayak
#

We can do whatever we want as long as the derivatives match the solution we give:

$y''' + 4y' = 3x^2 + 2x + 3$
We will assume y to be a polynomial. We should mind what degree it has.
Given that the smallest derivative is 1st order, that means that the original has 1 degree more than our result

flat frigateBOT
split kayak
#

the form of a generic 3rd degree polynomial is
$ax^3 + bx^2 + cx + d$

flat frigateBOT
mortal thicket
#

so a 5th deg poly?

split kayak
mortal thicket
#

wait

#

a 6th deg

split kayak
#

degree means the exponent of most order

#

in our result we have quadratic

#

so we will assume y to be cubic

mortal thicket
#

right okay

#

so same process are for general solution

#

so far

split kayak
#

the general form of a cubic is:

#

$y = ax^3 + bx^2 + cx + d$

flat frigateBOT
split kayak
#

You can work them out on your own if you doubt why but ill just give them straight:

$$y' = 3ax^2 + 2bx + c$$
$$y''' = 6a$$

flat frigateBOT
mortal thicket
#

then i just sove for a b c right

split kayak
#

yes, you add them up as your equation tells you, and find the coefficients

mortal thicket
#

am not already doing that for general solution?

split kayak
#

kinda, the process is obviously related, but the results and methods are usually more elaborated and require more knowledge

#

both on DEs and in general algebraic methods.

mortal thicket
#

ok

split kayak
#

thats why we get happy when they ask for a unique solution

mortal thicket
#

so that gives me 'a' solution for inhomogenous part

#

what ab the homogenous part

split kayak
#

nope, that gives the whole solution

mortal thicket
#

i thought a solution is homogenoyus part + inhomogenous part

#

also can i write my homogenous part like

split kayak
#

depends on the equation, but given that we can write any solution we want as long as it satisfies, this particular case is quite easy

mortal thicket
#

ok

#

but for my general i add the homogenous part with its unsolved coefficiant right?

split kayak
#

yes, again, thats why i asked if they want A solution or the general one

mortal thicket
#

i miswrote it tho

#

there should be a cos instead of a sin next to the B and a closing bracket

#

because this is what i was taught for second order homogenous solutions

split kayak
#

the homogeneous isnt 2nd order

#

its 3rd

mortal thicket
#

so can i just combine the solution where i get the complex conjugate and the real distinct root

#

and add them

#

so i would get $e^{\alphax}(Acos(\betax) + Bsin(\beta*x)) + Ce^{0}$

flat frigateBOT
#

Big Chicken

mortal thicket
#

cause the form $c_1 e^{2ix} + c_2 e^{-2ix} + c_3e^{0}$ is ugly with the complex number

flat frigateBOT
#

Big Chicken

safe radishBOT
#

@mortal thicket Has your question been resolved?

safe radishBOT
#
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thorny kelp
#

hi if by squeeze theorem, we get that the upper limit tends to 0, can we safely say that the lower bound limit is just 0

cedar widget
#

!xy

safe radishBOT
#

Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.

thorny kelp
#

like if i got f(x)<=g(x) where g(x) has a limit to infinity of 0

#

can i just say f(x)>=0

shy totem
shy totem
thorny kelp
#

oh

#

i see

#

so we need to prove f(x)>=0

shy totem
#

what is the exact question that you were asked?

thorny kelp
#

just like in general

shy totem
#

you cannot conclude anything about the lower bound of f(x) then

#

oh, what you can say is...

#

f(x) ≥ -infinity

safe radishBOT
#

@thorny kelp Has your question been resolved?

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hearty oyster
#

Im following an optimization tutorial by the ochem tutor and this part is confusing me, its probably a silly question sorry if it is but why isnt it also 2y? https://youtu.be/lx8RcYcYVuU?t=3271

This calculus video explains how to solve optimization problems. It explains how to solve the fence along the river problem, how to calculate the minimum distance between a point and a line, and how to maximize area while minimizing perimeter as in the case of fencing problems.

Get The Rest of the Video on Patreon:
https://bit.ly/41WNmI9

Dire...

▶ Play video
hearty oyster
#

i put the timestamp of the part im stuck on u just have to click the vid

fading mural
#

What makes you think it's 2y

hearty oyster
#

there are two rectangles

fading mural
#

You meant the orange one and the cyan one here?

hearty oyster
#

yes

fading mural
#

Okay so what's the area of the orange one

hearty oyster
#

xy

fading mural
#

and the other?

hearty oyster
#

xy?

fading mural
#

yeah

#

so total is 2xy

#

isn't it also what he got?

hearty oyster
#

yea that is what he got

hearty oyster
#

2x (y)

fading mural
#

So there're no difference

#

He treat both triangle as a whole

#

I meant rectangle

hearty oyster
#

i see

fading mural
#

A single rectangle

#

with dimension 2x and y

hearty oyster
#

yeah i get it now

#

alright thank you

fading mural
#

np

hearty oyster
#

.close

safe radishBOT
#
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zinc lintel
#

A circle is given with two distinct secant lines drawn from an external point P. One secant intersects the circle at points A and B in that order as one moves toward the circle from P. The other secant intersects the circle at points C and D in that order from P. All points A,B,C,D lie on the circle. You are told that the measure of ∠APC is equal to the measure of ∠APD. Using only geometric principles that hold for all circles—such as inscribed angle relationships, similar triangles, and properties of intersecting chords—prove a relationship that must always hold between the directed lengths PA,PB,PC, and PD. Your proof should: Establish at least one pair of similar triangles created by intersections of the secants with the circle. Explain why the angle relationships guaranteeing similarity must hold for any pair of secants drawn from the same external point. Use the similarity to derive a proportionality involving the products of segments formed along each secant. Conclude with a general statement describing the invariant quantity determined by the external point P and the circle. You must justify each step using circle theorems, triangle similarity criteria, or other accepted geometric principles.

zinc lintel
#

<@&286206848099549185>

zinc lintel
low echo
empty forge
zinc lintel
#

so this channel is usless

empty forge
#

There might be people that can help with this stuff

#

its just proofs are different from answering a problem

#

you have to you know write it out clear and consiely

zinc lintel
#

i did fr thre question

covert field
#

Brb

zinc lintel
#

alrught

covert field
zinc lintel
#

alrught thanks is this all the proof

covert field
#

Yes

zinc lintel
#

alright thanks

#

.close

safe radishBOT
#
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safe radishBOT
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spiral saddle
safe radishBOT
flat frigateBOT
#

Renato

gritty pasture
#

or what

spiral saddle
#

no, its from my first semester intro to proofs class

gritty pasture
#

ahh I see

#

I'm in high school still but lemme think rq

atomic sedge
atomic sedge
#

Also notice how the last term is 12p so that's automatically gonr

atomic sedge
gritty pasture
#

oh yeh ik that

#

oh wait

spiral saddle
#

care to elaborate?

atomic sedge
#

a^p-a

#

Is always divisible by p

spiral saddle
#

!noans

safe radishBOT
#

The purpose of this server is to help you learn, not to hand out answers. Do not ask someone to give you the answer directly.

atomic sedge
#

Oh ok

#

So do you get it

@spiral saddle

spiral saddle
#

you just spoiled me the answer

atomic sedge
#

No i meant like do you wanna know how to proceed

#

From fermats little theorem

spiral saddle
#

idk what fermats is neither who he is

atomic sedge
spiral saddle
#

what is the definition of fermats

empty forge
spiral saddle
#

sure

empty forge
#

bro have you learned it or not?

spiral saddle
#

i said yes already

#

what are you on about

empty forge
#

You said sure 💀

atomic sedge
empty forge
#

some ppl say sure and have no clue what the hell the stuff is 🥀

spiral saddle
#

,, a^p - a \equiv 0 \pmod{p}

flat frigateBOT
#

Renato

atomic sedge
spiral saddle
#

doesnt make any sense whatsoever for me

atomic sedge
#

It literally just says a^p-a is divisible by p

#

See let's take p=3

#

a=2

#

Now 2^3-2= 6

#

Which is divisible by 3

spiral saddle
#

its coincidental

#

you got lucky

atomic sedge
empty forge
spiral saddle
#

lets assume little fermats is right and his theorem works, then what?

fathom jewel
#

let's assume a proven theorem works (just in case)

spiral saddle
#

yes, any ideas?

safe radishBOT
#

@spiral saddle Has your question been resolved?

empty forge
#

@spiral saddle We want to solve for when 6p divides that equation

#

since 6 = 2 x 3 we first check if that equation is divisible by 2 and 3

spiral saddle
#

ok, now what

empty forge
#

idk

spiral saddle
#

wdym idk

#

you were cooking something...

empty forge
#

jk i have to take a call rq

#

wait a min

empty forge
#

K im back

#

so when we can rewrite the equation in modulo 2

#

so 17 ≡ 1 (mod 2)

#

45 ≡ 1, 374 ≡ 0, and 12 p ≡ 0

#

This means every term (when simplified) is even and so the equation ≡ 0 (mod 2)

#

So for any p the equation is divisible by 2

#

Now we see if the equation is divisible by 3

#

we get 17 ≡ 2 mod 3, 45 ≡ 0 mod 3 and so is 12, and -374 ≡ 1 mod 3

#

so we have the equation is ≡ to 2x2^(p+1)

#

this simplifies too 2^(p+2) +1

#

we then have 2^(p+2) ≡ to -1 which is same as 2 and we find that if p is odd then p is divisible by 3 while if p is even (which means 2) it is not divisible by 3

#

this means p=2 is excluded

#

@spiral saddle

#

Do you get this?

safe radishBOT
#

@spiral saddle Has your question been resolved?

empty forge
#

@spiral saddle do you get what I said above ?

safe radishBOT
#

@spiral saddle Has your question been resolved?

safe radishBOT
#
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dusky knot
#

i found the asnwer -36.23 but its saying im wrong can someone help

safe radishBOT
#

@dusky knot Has your question been resolved?

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supple locust
#

Can -2pi * sin(2pi x) be factored into 2pi (-1 * sin(x)) ?

plucky elk
#

Yes

#

You can plot both on desmos to verify

supple locust
#

Ooh, neat. Thanks.

#

Additional question, if you don't mind.

#

The reason I wanted to factor out 2pi in the first place is because I'm looking for the 0 of f'(c), which is -2pi sin(2pi x) .

junior raven
#

you just need to find the zeros of the sine function

supple locust
#

For f(x) = sin(x).

undone burrow
supple locust
#

Okay, that's huge. Thank you.

#

👍

#

Alright, I checked with my HW answer key. The 0 is supposed to be 1/4.

junior raven
#

that isnt a zero for your function

#

can you show the original question

supple locust
#

Sure thing. It's a bit long, though.

#

Apply Mean Value Theorem to find all points 0 < c < 1 such that f(1) - f(0) = f'(c)(1 - 0) for f(x) = cos(2pi x).

junior raven
#

the answer is c = 1/4?

supple locust
#

Since f(1) is equal to f(0), and f(1) - f(0) must be equal to 0, I figured that f'(c) would make the most sense being 0 as well.

junior raven
#

yes thats right

supple locust
junior raven
#

sin(2pi x) = 0

#

does not give 1/4 as an answer

supple locust
#

I checked in Desmos, and one of the f'(x) turning points was 1/4.

supple locust
#

It should be f(x) = cos(2pi x).

junior raven
#

okay

#

makes more sense now

supple locust
#

Oh, if it's pertinent, I did apply the Mean Value Theorem as best I could.

#

f'(c) = f(b) - f(a) / b - a so I plugged things in to get f'(c) = 1 - 1 / 1 - 0, which got me 0.

#

f(0) = cos(2pi x) =1 and f(1) = cos(2pi x) = 1.

junior raven
#

yes

supple locust
#

Oh, I'm the world's biggest dumbass.

#

I didn't need to find the zero of f'(c) because I could've just used the MVT. Welp, sorry for wasting your time.

#

I hope you have a wonderful rest-of-your-day.

#

Now to find all points 0 < c < 1...

#

.close

safe radishBOT
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sour wigeon
safe radishBOT
sour wigeon
#

how do I solve this?

#

clearly it is visible that $\alpha + \beta = \frac{\pi^4}{90}$

flat frigateBOT
#

Prathmesh

sour wigeon
#

but what next?

#

i am stuck

stoic saddle
#

how do you convert odd numbers to even numbers

#

rather how do you convert natural numbers to even numbers

sour wigeon
#

2n?

stoic saddle
#

yeah

#

so how would you convert the pi^4/90 sum to the beta sum

sour wigeon
#

by multiplying 1/2^4

stoic saddle
#

yeah

#

so now we have?

sour wigeon
#

$\beta = \frac{\pi^4}{(90)(16)}$

flat frigateBOT
#

Prathmesh

stoic saddle
#

so thats it

sour wigeon
#

what about alpha?

stoic saddle
#

put it into the equation you already have

sour wigeon
#

ohh wait

#

yea

#

got it

#

thanks!

#

.close

safe radishBOT
#
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tight orchid
#

I don't have a specific math problem I'm stuck on, I just need help understanding what radians are. I looked it up but I still don't think I fully understand it

tight orchid
#

Yeah

#

It's what we're learning right now but my teacher is making us learn it on our own and present it to the class this week

versed wave
#

just like degree, it's a unit of angle measurement

glacial cairn
#

Draw a circle of radius 1 and center O, and pick two points A and B on this circle that form an arc of length 1. The angle AOB measures 1 radian.

#

Since the circle's circumference is 2pi, the "full" angle (360º) measures 2pi radians

#

Then you can just scale all of that to apply to circles of different radii

tight orchid
glacial cairn
#

?

tight orchid
#

I saw a thing where to get degrees to radians and radians to degrees, I would have to multiply degrees by pi/180 for radians. And multiply radians by 180/pi for degrees. We also got a worksheet that had angles like 290° and it said to calculate the radians

open wedge
tight orchid
#

No

open wedge
#

the point of radians here, is the angle

#

when you bend the radius of a circle to make a curve that fits the circumference

#

and since you can fit $2\pi$ of that around the circumference

flat frigateBOT
#

1 divided by 0 equals Infinity

open wedge
#

and a circle is just 360 degrees

#

so $2\pi$ radians = $360$ degrees

flat frigateBOT
#

1 divided by 0 equals Infinity

open wedge
#

this video will help you understand better of it

#

@tight orchid

tight orchid
#

Ok, I'll look at it rn

#

Ok, I had to watch it twice to make sure. To find the amount of radians, it's basically seeing how many times the radius can fit in the same length as the circumference?

tight orchid
#

Ok, I understand it

open wedge
#

good

tight orchid
#

👍

open wedge
#

now prove that $\frac \pi 2$ radians is a right angle

flat frigateBOT
#

1 divided by 0 equals Infinity

tight orchid
#

I have to go to my next class now, so can I do it once I'm in passing period? In like 50 mins

open wedge
#

alr

vagrant ice
safe radishBOT
#

@tight orchid Has your question been resolved?

safe radishBOT
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lean nexus
#

I have no idea where to start, I mean row space is pertaining to non zero rows of a I think row reduced echelon of a matrix but that's all I got

peak estuary
#

if a vector x is in the row space of A, then x can be written as a linear combination of the rows of A

#

can x also be written as a linear combination of rows of B?

#

if yes that shows that the row space of A is a subset of the row space of B

#

then repeat in the other direction

lean nexus
peak estuary
#

the range of A is the same as the column space of A

#

so that is indeed the same thing, just rows instead of columns

lean nexus
#

where did you get the idea of introducing a vector x

peak estuary
#

to show that two sets are the same you take an element from each set and show that it is in the other set

lean nexus
#

I know ran(A)={y: Ax=y, x in R^n} but what would be set for row(A)

peak estuary
#

rs(A)={y: x^tA=y, x in R^m}

#

if you want to see it that way

peak estuary
lean nexus
#

i tried looking at the matrices by drawing it but still dont see a pattern

#

I'm assuming "kth row" is before the "mth" row

safe radishBOT
#

@lean nexus Has your question been resolved?

safe radishBOT
#

@lean nexus Has your question been resolved?

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swift salmon
#

Guys, what's wrong with my function?

safe radishBOT
plucky elk
#

what does the error say

swift salmon
#

Wait lemme graph it somewhere else

quasi bison
#

what happens if you mouse over the ⚠️ symbol

swift salmon
#

Now I'm tryna see the limit as x approach 0 of this function we can define as R(x)

quasi bison
#

the limit as x goes to zero?

#

with that sqrt(x-25) in?

swift salmon
quasi bison
#

!xy

safe radishBOT
#

Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.

quasi bison
#

we will not proceed any further until you show us the full original question

swift salmon
#

Ok.

#

y = \frac{\sqrt{x - 25} + \frac{2}{3x}}{\sqrt{x + 9} + \frac{3}{2x}}

#

$\lim_{x \to 0} \frac{\sqrt{x - 25} + \frac{2}{3x}}{\sqrt{x + 9} + \frac{3}{2x}}$

flat frigateBOT
#

GoldTrain

quasi bison
#

are you 200% SURE that this is EXACTLY WHAT THE TEXTBOOK SAYS

burnt notch
#

Send us a photo/screenshot of the exercise in the textbook

swift salmon
quasi bison
#

ok then your function is fucked up

#

its domain doesnt extend to 0

#

it's only defined for x ≥ 25

#

it makes zero sense to speak of its limit at x->0

swift salmon
#

Cuz It seems possible for me.

quasi bison
#

it's possible to push symbols around on a page if you have like, ≤0 regard for what things mean

#

which it really sounds like that's the case

swift salmon
#

I see.

#

Does the value at which a limit is approaching needs to be part of the domain of a function?

quasi bison
#

it needs to be an accumulation point of the domain

#

which may or may not belong to the domain itself

swift salmon
#

Wdym?

quasi bison
#

but 0 is in fact not an accumulation pt of [25,+∞) anyway

swift salmon
quasi bison
# swift salmon Wdym?

given a set X ⊆ R and a point a ∈ R, we say a is an accumulation point of X if:

any neighborhood of a has nonempty intersection with X \ {a}

quasi bison
swift salmon
quasi bison
#

ok let me rephrase that

swift salmon
quasi bison
#

any open interval centered at a contains at least one point of X that's different from a itself.

#

that is what it means for a to be an accumulation pt of X

#

intuitively speaking, an accumulation point of X is a point that "can be approached" from within X, without stepping on the target pt itself

swift salmon
swift salmon
quasi bison
#

there's no function at all yet

quasi bison
#

i think if you're going to self-study real analysis then you really should pick up a textbook and stop trying to be Euler II.

quasi bison
#

ok in that case

#

i guess you dont need the full and technical definition

swift salmon
quasi bison
#

"accumulation point", yes.

#

for a function whose domain is an interval (which basically all functions you encounter will be),
one can speak of the limit at a point either inside the interval, or at either endpoint, and this is regardless of whether the domain includes that endpoint or not.

swift salmon
quasi bison
#

real analysis is basically calculus but more rigorous.

swift salmon
swift salmon
quasi bison
#

that question sounds as strange as asking "what are the applications of syntax" in English class.

quasi bison
#

analysis is a huge ass field in math

#

like higher math. uni level stuff

#

so asking about its "applications" is like

#

youll get either wishy washy bullshit or just nothing

swift salmon
quasi bison
#

analysis == real analysis

#

but ok like

#

yknow im gonna be honest

#

youve given off strong vibes of someone who doesnt wanna listen and instead will act self entitled or whatever

swift salmon
#

What does the Epsilon-Delta definition of a limit states?

#

.close

safe radishBOT
#
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burnt notch
swift salmon
#

.close

burnt notch
#

Vague questions deserve vague answers...

safe radishBOT
#
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mortal forge
#

any one has a good resource to study laplace transform

vivid sparrow
mortal forge
#

thnx

vivid sparrow
#

Professor Leonard om youtube has good understandable calc 3 lectures, he has a diffeqs playlist but I haven't watched it, it should have info about laplace transforms though

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haughty loom
#

For all n >= 1, prove 12^{n} - 5^{n} is divisible by 7.

I was able to use the rule of exponents to be able to split 12^{k} - 5^{k} into 12 * 12^{k} - 5 * 5^{k} but I'm not sure what to do next? Thank you. There's a trick that the professor showed us where you can split one of the numbers into two portions and then go from there, but I'm not sure how you'd apply it in this case? Thank you.

haughty loom
#

Actually, wait, you'd split 12 into 7 + 5, wouldn't you.

#

Then distribute.

quiet plume
#

$12^{k+1} - 5^{k+1} = 12 \cdot 12^k - 5\cdot 5^k$, then yes split $12$ as $5 + 7$.

flat frigateBOT
#

Azyrashacorki

haughty loom
quiet plume
#

The big fraction is wrong (if you really want to show that you've factored it by dividing through, you need a multiple of 5 popping out) .and you're better off using equality symbols rather than implications.

#

But the last thing you wrote is right.

regal onyx
haughty loom
#

Ok, let me fix that, wait, so you don't divide it by 5 to get it back out?

haughty loom
#

To be frank I suck at this. 🤣

regal onyx
#

dw youll get better w practice

wild cape
#

why did u write all the equal signs as implies?

haughty loom
#

Bad habit mainly, that was my bad. Doesn't make sense in this context, I'm just used to conditional statements for some reason. Thanks for pointing it out

#

Ok, does something like this work?

#

🤔 Feels like I'm missing a step. Hm. Something to do with the 12^{k} * 7?

#

Wait..

regal onyx
#

i think that shows pk+1 is true when pk is true

#

because ur final expression is divisible by 7

wild cape
#

u should finish at the form integer*7. what is that integer?

haughty loom
#

The integers are defined as k and m.

#

So 7k, I think?

regal onyx
#

u should factor the final expression

haughty loom
#

I'm really bad at factoring so sorry about this, would I add 7 + 5 back to get 12, then factor 12 out?

regal onyx
#

so u get 7 * some integer

haughty loom
#

Ah ok, I get it.

#

You factor out the 7.

#

So 7(12^{k}+5m)?

#

Ah ok, sweet, thank you.

#

Does this look right to you guys? Again, thank you so much to the three of you

wild cape
#

this -> should be =

haughty loom
#

Crap, thank you, let me fix that real quick.

#

Alos...I wrote 5 instead of 7, oops

regal onyx
#

idk how much ur teacher cares abt ur statements but i would write that since n=1 is true and n=k => n=k+1 is true, the result is proved by mathematical induction for all n >= 1

haughty loom
#

Ok, thank you guys, does this look correct?

regal onyx
#

looks right to me

haughty loom
#

Ok, that sounds good, thanks a lot for checking this.

#

I just want to make sure for this question though that it looks right, if's still fine. 🙂

#

...Probably should just use = instead of \equiv, oops.

#

Ok, fixed that part. Do I have anything else wrong?

regal onyx
#

how do u suppose 4i - 2 = 2n^2

haughty loom
#

I'm gonna be honest, I'm not entirely sure. I was trying to follow this example that the professor laid out. Aren't we supposed to sustitute values to check to see if they're equal?

#

Unless I'm misinterpretting here.

regal onyx
#

ur usually sub values from ur n=k assumption

haughty loom
regal onyx
#

4i-2=2n^2 doesn't work because its the sum of i=1 to n of 4i-2 that gives 2n^2

haughty loom
#

I see.

#

Wait...so how does the substitution work then? If we can't replace i with k.

regal onyx
#

when u make ur k assumption u get sum from i=1 to k of 4i-2. ur substituting the entire sigma

haughty loom
#

Also, thanks for your patience, really do appreciate it.

#

OH I SEE.

#

Ok, that makes sense.

#

So we're substituting the entire sigma with k, and then we have to prove that for the entire sigma, with k + 1, all of these cases work.

regal onyx
#

im not sure ik what u mean, but when u break down the sigma with k+1 into a sigma with k and the k+1 term, thats when u sub k+1 and show that it's equal to 2(k+1)^2

haughty loom
#

I hope this is right now?

regal onyx
#

remember ur replacing the entire sigma so when u sub it becomes simply 2k^2

haughty loom
#

Wait, so we wouldn't care about the 4k+2?

regal onyx
#

once u add a conclusion sentence the proof works. though some equal signs make it a little confusing

regal onyx
haughty loom
#

Oh, I see. So there's no need to even spread them out in the "Continuing the distribution" section?

regal onyx
#

honestly once u had 2k^2 + 4k + 2 = 2(k+1)^2 ur basically done because you've now proved that n=k+1 is true using the assumption n=k

#

u dont have to distribute or anything afterwards

haughty loom
#

Ok, let me just rewrite that then.

#

You highlighted the sigma, did I write that part wrong somehow?

#

Wait, just get rid of the entire sigma then?

#

Ok. Final version.

#

Again, really, thanks for the patience.

regal onyx
#

this is good. i would remove what i highlighted for clarity. and finally i would conclude with: "since the result is true for both n=1 and n=k+1 assuming n=k is true, the result is true for all integers n greater than or equal to one"

#

"since the result is true for both n=1 and n=k+1 assuming n=k is true, the result is true for all integers n greater than or equal to one" goes in place of since k is an integer, therefore, for all cases btw

haughty loom
regal onyx
#

oh lol then nvm haha

haughty loom
#

Also, is it fine if you check this final one too? And those should really be all. Again, really appreciate the help so far, mate. I just have to survive this class. 🙂

#

Actually, I added more of a clearer statement at the bottom.

#

Actually here, it's shorter.

regal onyx
#

this part might be repeated

haughty loom
#

Oh crap, oops.

#

Thank you for catching that.

#

Ok, final version.

#

I'm just writing the distribution out because I suck at algebra, so I need to actually see what it looks like.

regal onyx
#

this looks right

haughty loom
#

Have a good day/night, wherever you are. Again, really do appreciate the help.

#

.close

safe radishBOT
#
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safe radishBOT
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sinful citrus
safe radishBOT
sinful citrus
#

im so confused

#

is this the answer?

#

.close

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shell loom
safe radishBOT
shell loom
#

please solveeeeee im so stuckk

rigid inlet
errant rapids
#

Brother you asked the exact same ques but different numbers before

#

Try to understand the logic then at least not just the answers

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dull sequoia
#

im currently looking at separation of variables to solve the heat equation, i dont get why we keep lambda = 0 when looking at the sine expansion of X(x)

dull sequoia
#

since you already start this part by saying suppose lambda < 0, how can you then pick k \in \bZ such that lambda = 0?

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#

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south lynx
#

i need help with the first part of the question. i looked it up and one of the most common solutions was (a, b) R (c, d) iff a < c or (a = c and b < d) and it does make sense, but i cannot figure out how did we think of it? in general too, i am having trouble with coming up with examples of this topic

dull sequoia
#

i mean you want to compare 2 pairs of numbers

#

it's a lot like reading words on a page

#

in english you read top to bottom, left to right

#

as in, if 2 words are on the same column you read the top one first, if 2 words are in the same row you read the left one first

#

here you read the first entry first, compare them, if they are the same then compare the 2nd entries

south lynx
#

so like dictionary order?

mortal sandal
#

Exactly

#

It's often called the lexicographic order

#

which I think is a fancy word for the same thing

south lynx
#

what other examples could be there for this question?

mortal sandal
#

If youve seen the diagonal paths trick

#

You can do that, basically bijecting to N and using that ordering

#

It's a little easier to see that that's a well-order

south lynx
#

i see

#

it is still a little hard to get the intuition for it

mortal sandal
#

Yeah the definition of well-order is a bit weird

south lynx
#

okay, thank you for the help!

#

.close

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#
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mortal sandal
#

No problem

safe radishBOT
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clever gale
#

A² = ?
hence A^n = ? for n ≥ 2?

ornate wyvern
#

find A^2, A^3, A^4 ull notice a pattern

#

utilise that pattern to get the answer

winged flare
#

you could alternatively cheat a bit and find det(A)

#

but try finding the pattern first

#

there are some other problems where the cell contents are not so simple

ornate wyvern
winged flare
#

no i meant it like the cells in a matrix

ornate wyvern
#

the elements right

winged flare
#

yeah

ornate wyvern
#

yea sure elements can b more difficult

clever gale
winged flare
#

|A| = 0

#

|A^2025| = |A|^2025 = 0

#

option C

ornate wyvern
#

!noans

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#

The purpose of this server is to help you learn, not to hand out answers. Do not ask someone to give you the answer directly.

winged flare
clever gale
#

oh you used the MCQ answers to infer that

#

I see

ornate wyvern
winged flare
#

oh

safe radishBOT
#

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hoary seal
#

heyy I understand perumation and combination definition but I am not able to see or visualise their difference

hoary seal
#

can u possibly show me through an example, that might help

junior raven
#

order matters in permutation

hoary seal
#

yes

junior raven
#

so if there are 5 flavours of ice cream

#

and youre getting two scoops

hoary seal
#

yep

#

2 scoops or 2 flabours?

junior raven
#

2 scoops of 2 flavours

#

vanilla on top and chocolate below is not the same as vanilla below and choclate on top

#

but for combination

#

those two ice creams would be equivalent

hoary seal
#

can u use this example

#

to explain permutation and comb

junior raven
#

so red blue green and green blue red are not the same in permutation

#

but they are the same in combination

hoary seal
#

yes I understand that but

elder moss
hoary seal
#

I feel like something else I am missing

#

iin my understanding

austere goblet
#

in your own terms

#

then we'll check you

#

use whatever example you please

hoary seal
#

permutation is selection of items

#

but order matters

#

combination is the same but order does not matter

austere goblet
#

then suppose I have three coins. how many combinations of those three coins are there? how many permutations?
(call them A, B, C if you want to list them)

hoary seal
#

3!

#

6 ways

austere goblet
#

I asked two questions.

hoary seal
#

ABC - 1 combination

3! for permutation = 6 ways

burnt notch
#

Correct