#help-28

1 messages · Page 287 of 1

delicate torrent
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hint: use the identity $\sin^2 \theta + \cos^2 \theta = 1$

glossy valveBOT
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1 divided by 0 equals Infinity

craggy tapir
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there's nothing to prove

lime trellis
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do you mean simplify?

torn jolt
delicate torrent
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solves all problem

torn jolt
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Alr lemme try

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Yall im good i was afraid to try

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Thanks

glacial pendant
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Hello

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Guys

delicate torrent
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!done

torn jolt
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.close

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

delicate torrent
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delicate torrent
craggy tapir
# glacial pendant Guys

are you trying to ask a question? if so you should use a channel in the available category

glacial pendant
#

Is it tan^4A

craggy tapir
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# glacial pendant Is it tan^4A

As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.

glacial pendant
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Oh sry

delicate torrent
dusk nebula
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# glacial pendant Is it tan^4A

As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.

glacial pendant
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How to check then?

torn jolt
dusk nebula
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idk

glacial pendant
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10th standard

torn jolt
torn jolt
glacial pendant
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I just solved this with identities I knew

glacial pendant
torn jolt
torn jolt
glacial pendant
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Oh ic then syllabus is diff

glacial pendant
torn jolt
glacial pendant
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Ye

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In 11th it is more diverse

torn jolt
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I promise there gonna be 20 more next term

torn jolt
glacial pendant
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Yes

torn jolt
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I’m actually gonna cry over trig so bye

sour shore
glacial pendant
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I just know sin^2 + cos ^2 = 1

torn jolt
glacial pendant
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cosec^2-cot2= 1

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sec^2 - tan^2 = 1

torn jolt
sour shore
glacial pendant
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Trigo is fine till 10th

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Idk about 11th

torn jolt
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U substitution ftw

glacial pendant
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Can u solve this one? @sour shore

glacial pendant
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I was right who the hell said no @torn jolt

glacial pendant
sour shore
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(TanA)^4

glacial pendant
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I started doubting my self

torn jolt
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It’s 4tanA

glacial pendant
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No

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It's in exponent

glacial pendant
torn jolt
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Nuh uh my key says otherwise

glacial pendant
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AI also says the same

delicate torrent
glacial pendant
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How could she get 4😭

delicate torrent
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😭

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that's the damn problem

delicate torrent
glacial pendant
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Ya I mean ya

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harsh cove
#

how can i solve log3 11 by hand, i know how to work out logs when the base and n can be represented as a power of a common factor ( like 4 and 8 can be represented as 2^2 and 2^3), but 3 and 11 are both prime numbers so im not sure how i can work it out

onyx glen
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by hand? in exact form? log_3(11) is already as simplified as it possibly can be

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are you required to compute it to 5 decimals or something (BY HAND) or what

harsh cove
delicate torrent
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$3^{2x} = 11$

glossy valveBOT
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1 divided by 0 equals Infinity

delicate torrent
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find $x$

glossy valveBOT
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1 divided by 0 equals Infinity

delicate torrent
glossy valveBOT
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1 divided by 0 equals Infinity

delicate torrent
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you can keep it as it is

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if you tried to find the decimal representation then it would only be an approxiate => wrong answer

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@harsh cove

harsh cove
delicate torrent
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yes

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$x = \frac{\log_3 11}{2}$

glossy valveBOT
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1 divided by 0 equals Infinity

delicate torrent
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this is valid already

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or if you want to convert to $\ln$, you can

glossy valveBOT
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1 divided by 0 equals Infinity

harsh cove
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im gona check the answer sheet to see if thats what i can put down

delicate torrent
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unless if your question asks to approximate

harsh cove
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it says x = 1.09,

delicate torrent
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then you would need to work on the decimal representation depend on what the question asks you

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!original

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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.

delicate torrent
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give me the whole context

harsh cove
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it just says

delicate torrent
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,w calc log_3(11)/2

delicate torrent
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.

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,w calc 3^(2*1.09)

delicate torrent
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this is what happens if x = 1.09

harsh cove
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tbh the question doesnt specify whether its calculator or not so i think that it is calculator given that giant decimal

delicate torrent
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or safer you can do $\frac{\ln 11}{2\ln 3}$

glossy valveBOT
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1 divided by 0 equals Infinity

delicate torrent
harsh cove
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okk thank you

#

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round gust
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round gust
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what does it mean to rotate this figure around the x axis

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i need to rotate it around the x axis

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so that TBC is in the xy plane

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and S has a positive y- coordinate

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do i just

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move it towards the right?

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like

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towards the positive y direction

spiral vigil
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if i understand it correctly it's like this

round gust
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i know the points

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T(0,0,0)

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B(5,5,12)

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C(-5,5,12)

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S(0,0,24)

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now i rotate

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i need to find the new coordinate of S

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my reasoning is:

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the distance from T to BC is 13

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and then i go an extra 12 (distance from abcd to S)

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so the new y coordinate for S would be 13 + 12 = 25?

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because i am thinking that d(T, BC) = d(T, B'C')

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=13

round gust
round gust
spiral vigil
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the distance is the same but what's the angle?

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may be helpful to look at the yz projectin

round gust
round gust
glossy valveBOT
round gust
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I thought that

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I can calculate the angle at which TB rotates

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So the angle between TB and the xy plane

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Which is 59.49°

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So then i though

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That

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TS rotates at the same angle as TB

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So TS should also rotate at 59.49 degrees

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While keeping its x coordinate unchanged

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So i made a triangle

covert remnant
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answer this

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i can t solve it broo

round gust
round gust
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or im i approaching it wrong

turbid badge
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covert remnant
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@round gust Has your question been resolved?

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@round gust Has your question been resolved?

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@round gust Has your question been resolved?

round gust
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omg i did it

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after 4 hours

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yay

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.close

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toxic sage
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can someone explain the alternating subgroup to me? i don't get it

cedar cloud
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did you understand the permutation group?

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S_n

toxic sage
fathom saddle
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This channel is closing

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Will lock soon. You'll need to grab your own. #help-2 is available

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Well, then again may not lock soon. It's been open for an hour and a half lol

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But will lock randomly

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molten torrent
#

Hello! I need a bit of help with verifying trigonometric identities! I've been stuck on my homework for the last hour T-T

regal thicket
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What exactly are you struggling with?

molten torrent
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Ive never been too good with fractions, so far I've made it here

stone matrix
molten torrent
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I don't know how, I forgot 😅

digital void
# molten torrent

can you explain the step you took from line 1 to 2? what did you multiply with exactly?

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oh nvm sorry

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you expanded the expression

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hmm perhaps you shouldnt expand quite yet, to avoid confusion in the next steps

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do you know how to cross multiply? id vouch for that in this case

prime pier
glossy valveBOT
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ηασιβ ♥

delicate torrent
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fractions inside fractions are ugly, so try to get rid of that quickly

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and the 1 on the numerator will flip the fraction you will have in the denominator

molten torrent
molten torrent
delicate torrent
molten torrent
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It's cosx right?

delicate torrent
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no

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but you're close

molten torrent
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Cos2x ?

delicate torrent
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yes

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$\cos^2 x$

glossy valveBOT
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1 divided by 0 equals Infinity

molten torrent
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So what do I do with the cosx ?

delicate torrent
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then make it the same denom

molten torrent
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I can just make cosx into cos2x ?

delicate torrent
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ya?

molten torrent
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Ok

delicate torrent
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$\frac{1}{\cos x}$

glossy valveBOT
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1 divided by 0 equals Infinity

delicate torrent
#

multiply both numerator and denominator by $\cos x$

glossy valveBOT
#

1 divided by 0 equals Infinity

delicate torrent
#

what you got @molten torrent

delicate torrent
#

that helps a lot when you're struggling in math

molten torrent
delicate torrent
#

yep

molten torrent
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I think I'm getting it a bit more but I don't know how to get the fraction out of the fraction

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Should I start over and separate the tan2x and secx ?

molten torrent
#

Yeah I think it's stuck

formal snow
#

kiểu

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1/(a/b) = b/a

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$\frac{1}{\frac{a}{b} = \frac{b}{a}$

glossy valveBOT
#

^the shark
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formal snow
#

$\frac{1}{\frac{a}{b}} = \frac{b}{a}$

glossy valveBOT
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^the shark

molten torrent
#

Like this right?

formal snow
molten torrent
#

Thank you all! I did it!

formal snow
molten torrent
#

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formal isle
#

Can anyone help me with question 9. I dont know why my answer is different from the answer key ( ignore the writing its wrong )

sleek torrent
#

<@&286206848099549185>

glossy valveBOT
outer lotus
#

What's your answer

ocean sluice
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well above the problem

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i think

formal isle
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That’s the formula for part a

ocean sluice
formal isle
#

Cause like 0.045 is monthly and it’s compounded interest so it to the power of 5 months

outer lotus
ocean sluice
outer lotus
#

Via, what is your answer for a)

formal isle
outer lotus
#

What are the right answers

formal isle
#

It’s 3738.55 for a and 675 for b

ocean sluice
#

,w (17000(1+0.045)^5) - 17000

ocean sluice
outer lotus
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And then find the difference

formal isle
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Ohhh bruh

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😔

formal isle
#

Tysm catthumbsup

outer lotus
formal isle
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Wait.

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How does that get the answer for a tho?

outer lotus
formal isle
#

OHHHH

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Tysm !

#

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old edge
#

wait is there anyone that knows how to factor x^4+1 using something similar to completing the square

rare dock
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would you know how to factor x^2 + 1?

old edge
#

over imaginary numbers but my math teacher told me i can factor x^4+1 without imaginary?

rare dock
#

oh well yes sure

rare dock
old edge
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am i slow idk how to do it

whole lily
#

\begin{aligned}x^{4}+4y^{4}&={\bigl (}(x+y)^{2}+y^{2}{\bigr )}\cdot {\bigl (}(x-y)^{2}+y^{2}{\bigr )}\&=(x^{2}+2xy+2y^{2})\cdot (x^{2}-2xy+2y^{2})\end{aligned}

glossy valveBOT
#

Roy
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old edge
#

wait ur a genius

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TYSM

whole lily
#

No worries. It's used a lot in integration

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\begin{align*}
x^{4}+1 &= x^{4}+1+2x^{2}-2x^{2} \
&= \left(x^{2}+1\right)^{2}-2x^{2} \
&= \left(x^{2}+1-\sqrt{2}x\right)\left(x^{2}+1+\sqrt{2}x\right)
\end{align*}

glossy valveBOT
whole lily
#

And yes, it's the same idea as completing the square

old edge
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where do the 2x^2 - 2x^2 come from

whole lily
#

We basically add those terms to force the "completing of the square"

old edge
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oh but how do you come up with them

whole lily
#

Because $\left(x^{2}+1\right)^{2}=x^{4}+1+2x^{2}$

glossy valveBOT
whole lily
#

Replace each x^2 term with x and it's basically the same as completing the square

old edge
#

ok got it ty

whole lily
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@old edge Has your question been resolved?

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whole lily
#

I was gonna say, in case if it was for integrating $\int \frac{1}{x^{4}+1}dx$ using partial fractions, there are more efficient methods

glossy valveBOT
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still marlin
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still marlin
#

help

#

i forgot how to solve this typa stuff

keen vector
#

!status

full forumBOT
#
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
keen vector
#

@still marlin

still marlin
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1

still marlin
keen vector
#

really you don't know where to start?

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how about simplifying the denominators

still marlin
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i mean are u supposed to take x2=t y2=p and then solve 4 equations?

keen vector
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yes basically

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it's a system of linear equations

still marlin
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dang i thought there was a better solution which wasnt click in my head

keen vector
#

so you did know where to start

still marlin
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yeh ig so lol

undone radish
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just set them equal

still marlin
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wdym

keen vector
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they're all equal to 1

still marlin
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can someone find the telescoping series here? ik i can solve this with gamma functions but

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x+n-x-1 gives n-1 but how do i make it a telescoping sum

full forumBOT
#

@still marlin Has your question been resolved?

jovial junco
round sparrow
#

You can do it without gamma function

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Let’s call each term u_n

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What is u_n+1 in function of u_n (and of n) ?

still marlin
#

still wanna do it with telescoping

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i gtg now ill come back to this later

#

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summer creek
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summer creek
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8c2?

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Or 8c2/2=14

queen flame
summer creek
#

Why?

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A handshake to B

B handshake to A is same

queen flame
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1 hand shake =>1 pair of people so we find how many pairs of two can be made

queen flame
#

So 8C2

onyx glen
summer creek
#

8P2/2=8C2?

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@onyx glen

stone matrix
summer creek
#

I see

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Thanks

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grave elm
#

If we have a rhombus with ratio of side to height 5 : 3, what's the ratio of diagonals?

grave elm
#

what i did is u1^2 + u2^2 = 100 and u1*u2 = 30, divide it and get r + 1/r = 10/3. But is there anything more elegant?

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r is the ratio u1 / u2

torn jolt
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10?

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shouldnt that side be 5

grave elm
torn jolt
#

oh ok i thought the height was 3

torn jolt
# grave elm

take the altitude so that it starts from the vertex

grave elm
torn jolt
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and you get a 3-4-5 right triangle

grave elm
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oh shit

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wait no

torn jolt
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oh yeah nvm

grave elm
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oh u do

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idk what next though

torn jolt
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oh ok yeah

bright bronze
torn jolt
grave elm
torn jolt
bright bronze
#

you can see the diagonals as hypotenuses of two right angled triangles of sides 3&9 and 3&1

grave elm
#

That's so cool

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and the ratio is obviously 3

bright bronze
#

yes

grave elm
#

beautiful

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thanks

#

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torn jolt
#

Hi

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torn jolt
#

So
Consider 4 boxes , where each box contains 3 red balls and 2 blue balls . Assume that all 20 balls are distinct. In how many different ways can 10 balls be chosen from these 4 boxes so that from each box at least one red ball and one blue ball are chosen?

onyx glen
#

!status

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6. I have completed the problem and don't need help anymore. Thank you.
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torn jolt
#

Each box has 3 red ball and 2 blue ball so firstly i picked 8 red balls to ensure 1 red ball and 1 blue ball is taken from each box and then we can find the ways to find the other two balls from the remaining. So 3⁴.2⁴ would be the no. Of ways to choose . In this case for 8 balls

hoary ember
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what did you do with the 2 other balls that are to be chosen?

torn jolt
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Ist one where 2 balls can be choosen from 1 box and 2nd case where balls are choosen from 2 boxes

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Ofc subcases of colours will be formed

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Total 66 ways

hoary ember
#

did you consider the fact that a blue ball (call this one A) chosen from the first 8 balls then another blue ball chosen from the 2 balls (call this one B) is counted twice with B first then A?

torn jolt
#

While forming the cases it was considered

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<@&286206848099549185>

vapid shell
#

Hi

torn jolt
vapid shell
#

Tell I try

torn jolt
vapid shell
torn jolt
#

Maybe show ur work

torn jolt
onyx glen
#

bc like, you're essentially marking the first red and first blue ball with a sticker

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and sometimes this leads to overcounting by 2, sometimes by 4, sometimes not at all

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here's a better way to do it

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there are only two distributions of ball counts:
4-2-2-2 and 3-3-2-2 (up to box order)

onyx glen
torn jolt
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# vapid shell 1296 is ans

As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.

vapid shell
torn jolt
onyx glen
#

so for 4-2-2-2: first pick which of the 4 boxes you take 4 balls from, then find the number of ways to pull from each box

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with the 2s it'll only be RB, with the 4 it will be RBBB or RRBB

onyx glen
#

that's the first factor yes

vapid shell
torn jolt
onyx glen
torn jolt
#

Pls let be understand

onyx glen
#

but "yes it is" "no it's not" is unproductive so leave it now

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unless you wish to share your own logic to see where you must have gone wrong

vapid shell
#

Let me try again

onyx glen
#

!nosols, as a reminder

full forumBOT
#

As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.

torn jolt
#

Why is baseline method wrong

vapid shell
torn jolt
vapid shell
torn jolt
#

The answer is 21816 bro

vapid shell
#

How

torn jolt
#

Idk where u checked from

#

Even ai overcount here

vapid shell
#

I solved

torn jolt
vapid shell
#

What ai

torn jolt
#

I mean its pretty obvious the answer wouldn't be a 4 digit

vapid shell
torn jolt
#

His answer was the same as mine which is 85536

#

<@&286206848099549185>

vapid shell
#

Bro your qualification

torn jolt
vapid shell
#

I agery my answer can be wrong but more than 10000 is never be ans of it

torn jolt
queen flame
onyx glen
onyx glen
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# torn jolt Even ai overcount here

Please do not trust ChatGPT or similar AI tools for mathematical tasks, as they often generate output which "sounds correct" but has numerous factual or logical errors. Use of these AI tools to answer other people's help questions is strictly against server rules (see #rules).

torn jolt
warped frost
torn jolt
#

Where i manually counted as 3⁴.2⁴

onyx glen
#

actually sometimes also by 3

torn jolt
queen flame
torn jolt
# onyx glen

Well if you do it by your way you are still marking stickers on balls

#

How does that differ

onyx glen
#

maybe i can illustrate with a simpler example if you are ok with that?

torn jolt
onyx glen
#

yes, that's basically the logic

torn jolt
#

Yeah i get it

onyx glen
#

let's say we have a standard deck and we want to know the number of ways to draw 3 cards from it such that there is at least one spade

a mistaken way to do it would be 13 * 51C2, with the reasoning of "draw a spade first then two other whatever cards"

#

but then like, if you look at the hand {Q♤, 6♤, 2♤} how can you tell which one was the first drawn spade

#

you can't

torn jolt
#

Now can you please explain the correct method to solve this

onyx glen
torn jolt
#

Only 1 case

onyx glen
torn jolt
queen flame
onyx glen
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sour torrent
#

$\int^{+\infty}_{-\infty} \cos(t) \delta(t) \mathrm dt$

glossy valveBOT
sour torrent
#

Can I say that since the delta is different from 0 in a very small neighborhood of 0, then the cosine assumes a constant value?

#

i.e cos(0) ?

#

in the sense that in that small neighborhood the cosine function almost always assumes the value 0?

#

so

#

$\cos(0) \int^{+\infty}_{-\infty} \delta(t) \mathrm dt$ ?

glossy valveBOT
sour torrent
#

and now I can think of the delta as a rectangle with base $\epsilon$ and height $1/\epsilon$ then area = 1 ?

glossy valveBOT
sour torrent
#

so the result would be cos(0) = 1 ?

rigid crescent
#

Yes that works. In general the delta function obeys this property given f is continuous at t=t_0

sour torrent
#

Yes, I'm trying to see how these results come out using some approximations (like the normalized Gaussian).

rigid crescent
#

the reasoning is because the delta function concentrates most of the weight near t=0

sour torrent
rapid rain
sour torrent
#

i was thinking about this graph so when epsilon -> 0 the hight increase

rapid rain
# sour torrent

In the meantime you can think about it like a limit of functions like that where a -> 0

sour torrent
#

and the base get smaller

#

so area = epislon * 1/epsilon = 1

sour torrent
#

that is, how should I justify those results that follow from the properties above?

#

i was thinking about that

#

ie in an small interval espilon i can say that che function always assume the value 0

#

i mean $\approx x(0)$

glossy valveBOT
rapid rain
sour torrent
#

instead if i have like $\delta(t-1)$ then

glossy valveBOT
sour torrent
#

$\approx x(1)$

glossy valveBOT
sour torrent
#

can I imagine an interval epsilon that contains the entire bell in point 1 and in that interval the function is approximated to a constant?

rapid rain
glossy valveBOT
#

Rafilouyear2026

sour torrent
#

how can i think this as ?

rapid rain
#

if a < 0, you get $\int_{-\infty}^{\infty} x(t)\delta(at) dt = \frac 1a\int_{\infty}^{-\infty} x(\frac ta)\delta(t) dt$

glossy valveBOT
#

Rafilouyear2026

rapid rain
#

the bounds are swapped because "u = at" runs through the real line from right to left

rapid rain
# sour torrent

I guess to understand this formula, think that delta is once again the limit of those plateau functions

#

if you now look at plateau(at) instead of plateau(t), you change the pace at which you run through the plateau

#

so going faster/slower at a rate of "a" means the area is changed by a factor of 1/|a|

#

it's the same as if you changed the height of the plateau by 1/|a|

sour torrent
#

mm ok

full forumBOT
#

@sour torrent Has your question been resolved?

sour torrent
#

so $\int^{\infty}{\infty} x(t) \delta(at) \mathrm dt$ = $x(0) \int^{\infty}{-\infty} \delta(at) \mathrm dt$

glossy valveBOT
sour torrent
#

and $\int^{\infty}_{-\infty} \delta(at) \mathrm dt = 1/|a|$

glossy valveBOT
sour torrent
#

since Area = epsilon/|a| * 1/epsilon = 1/|a|

#

right ?

#

so i can also this as

#

$\int^{\infty}_{-\infty} x(t) (1/|a| \delta(t)) \mathrm dt$

glossy valveBOT
sour torrent
#

so $\delta(at) = \frac1{|a|} \delta(t)$

glossy valveBOT
rapid rain
#

exactly

sour torrent
#

thanks

#

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restive nimbus
#

could someone help me solve this

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onyx glen
#

$\cos(z) = \frac12 (e^{iz} + e^{-iz})$

glossy valveBOT
onyx glen
#

though one is inevitably led to wonder why we are asked to find "the" value of z satisfying this equation when in fact there's infinitely many of them (as cos does not lose its 2pi-periodicity when transitioning from R to C)

restive nimbus
#

so theres infinite amount of answers..?

#

wait that makes sense

#

but like how do i get one of the solutions

#

i did rewrite it as cos(x+iy) and the used some formulas to get it to cosxcoshy -jsinxsinhy

onyx glen
#

anyway like. ok. sure.

#

you want sin(x) sinh(y) = 0 and cos(x) cosh(y) = 3 and x, y both real.

restive nimbus
#

okay so i got x=2kpi and y cant be 0 i think

restive nimbus
#

also yeah we use j lol cause i gets confused with current or something like that

onyx glen
restive nimbus
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Couldn't find an attached image in the last 10 messages.

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signal wasp
#

Huh?

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pliant hornet
#

i get no result and I don't know what i did wrong, do anyone know?

gritty rose
#

solve for b here and plug it into the line below

#

then you can try to solve for lambda

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timber vapor
#

hello how would i solve this if there’s a hole on coordinates that have the x value of 0?

steep elbow
timber vapor
steep elbow
timber vapor
#

right

steep elbow
#

but you are correct in the sense that, if x is close to 3, then f(x) is close to 0

#

now let's set u = f(x)

#

if u is close to 0, what is f(u) close to?

timber vapor
#

im not sure if i understand correctly

#

because i thought then you’d find the y value when x is 0?

full delta
#

Think of the limit in terms of left and right hand limits

#

lim (x->3)f(x) approaches 0 but only from one direction

steep elbow
timber vapor
#

i see

steep elbow
#

for example, if x is near 4, then f(x) is near -3

#

even though f isn't defined "at" x = 4

timber vapor
#

got it

#

how would i write an answer tho cuz i tried another method and it said it was wrong

full delta
#

You know what left and right hand limits are right

timber vapor
#

yes

#

but this one doesn’t specify

full delta
#

Can you tell me if we should be concerned with the right hand limit of f(f(x)) in this case

timber vapor
#

yes i think

full delta
#

Why do you think so

timber vapor
#

because it approaches 3

full delta
#

x approaches 3

#

what does f(x) approach

timber vapor
#

f(x) is the y value right?

full delta
#

Uh yeah

timber vapor
#

there’s two points that aren’t filled on the y axis

#

so one of those?

full delta
#

as x approaches 3, f(x) approaches only one value

timber vapor
full delta
#

Yeah

#

It approaches 0 but only from the negative side

#

That's why we need not be concerned about the right hand limit of f(f(x))

#

Think of f(x) as u

#

u is approaching 0 only from the negative direction

timber vapor
#

i see

full delta
#

Is that the answer you gave

timber vapor
#

no thats an option if the answer is does not exist

full delta
#

Yeah so what do you now think the answer is

timber vapor
#

it doesn’t exist?

full delta
#

Why do you think that

#

Since we are being asked the left hand limit only

#

What could the reason be for it to not exist

#

That can only happen if it blows up to infinity or has a gap in the domain

#

Around* that point

#

In its neighborhood

#

Both of which isn't teue

#

Theres only a point discontinuity

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cold sail
#

how do u obtain the pressure scale without using the stokes eqs i dont get it

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nimble ridge
#

My answer was marked incorrect, but I'm not sure where I went wrong

nimble ridge
#

,rccw

glossy valveBOT
nimble ridge
#

I believe the Riemann sum is supposed to be uneven and based off the values in the table in this case.

#

Will be AFK until updated.

queen crater
#

Holy handwriting

#

,calc 42724+63108+33697+74283

glossy valveBOT
#

Result:

70616
queen crater
#

I don't see the problem with 9.a

nimble ridge
#

Hmm. Could just be my teacher, he always overlooks errors when making online quizzes on which I submit these answers.

#

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gloomy rampart
#

@nimble ridge is this composite functions

nimble ridge
gloomy rampart
#

i mean

#

algebra

nimble ridge
gloomy rampart
#

i mean

#

it is a function

#

im stupid

#

nvm

#

dw

#

wait is it..?

#

it is

#

right

#

@nimble ridge

nimble ridge
gloomy rampart
#

im sorry 😭 im tryna learn calc

drowsy niche
drowsy niche
nimble ridge
drowsy niche
gloomy rampart
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hoary current
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nimble ridge
hoary current
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timber vapor
#

i tried -3 and 2 and it marked it as wrong?

devout valley
#

Why -3? catThink

#

(+ do you think there may be more?)

timber vapor
#

im looking at examples and some of them mark it correct when there’s a hole and like a filled dot on top of it

timber vapor
devout valley
timber vapor
#

yes

devout valley
#

Fair, but here, it's a bit different Hehe do you understand what limits basically are?

timber vapor
#

yes i do!

devout valley
#

Could you explain limits a little bit to me then? catlove

timber vapor
#

so like for this example it’d be the values of y approaching 1 on both sides

devout valley
#

Yep, and from both sides, what do those y values approach? nyasSnuggle2

timber vapor
#

wait sorry where do i look on the graph to find that out

devout valley
#

Basically, if you take your finger, and put it on the graph, and then move towards the point, doing that from each sides catlove

timber vapor
#

so one of them would be 2 right

devout valley
#

Which one do you mean? catThink

timber vapor
#

there’s a point at (2,1)

devout valley
#

Yep, that would be a valid answer for our question, and we're also lucky that there are no holes there SCgoodjob2

timber vapor
devout valley
#

I wanted us to also work through that point -3 though, to see if we were right or not pikathink

timber vapor
#

okay got it

#

would the point at (-3, 1) override the hole

devout valley
#

It wouldn't, no SCsadkittyNO basically for limits, you don't really care what actually happens at the point you're going to, so for this example, we don't care that the function value at -3 is actually 1, we only care about what it looks like it's going to be when we approach from either side catokay

#

If that makes sense?

timber vapor
#

ooh yeah okay

#

so -3 wouldn’t be an answer

#

and same with -5 and -7

devout valley
timber vapor
#

the points don’t overlap the hole tho right

devout valley
#

They don't, but we don't care too much about what those points are, or if they don't overlap the hole or not catlove

#

All we care about is if we try to approach the point from both sides, what does it look like we're going to get to (and if those happen to be the same thing!)

timber vapor
#

ooooh okay

#

so -7 would be an answer then

devout valley
#

It would catYes

timber vapor
#

okok got it

devout valley
#

Any others too? nyaTease1

timber vapor
#

hmmm

#

6?

devout valley
# timber vapor 6?

Not 6, because we don't get close to the same thing if we go from left to right SCsadkittyNO

timber vapor
#

ah i see

devout valley
#

I'll give you a hint, you said the other one already somewhere nyaTease1

timber vapor
#

-5?

#

would that only be if i approach it from the right side

devout valley
#

Yep that one SCyay and -5 works from both sides, if e.g. you moved from left to right, or right to left, you would be getting closer and closer to 1 as you get closer to -5

timber vapor
#

got it thank u sm

#

so far i have 2, -7 and -5

devout valley
#

Yep, do you think there are any more, or do you think those are all? pikathink

timber vapor
#

it can’t be -2 cuz both points there r holes right

devout valley
#

It isn't -2, no, but more because while moving from left to right we do get closer to 1, when we move from right to left, we don't get close to 1, but instead to -1 catlove

#

So the [overall] limit doesn't even exist there SCshocked

timber vapor
#

got it

#

so those 3 should be it i think

devout valley
#

(it's a similar story for 6, moving right to left we approach 1, but moving left to right we actually approach 3 instead, so no limit there either nooo)

devout valley
timber vapor
#

got it thank u so much!! have a good one

#

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void jay
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onyx glen
#

arithmetic bullshit, no doubt

void jay
#

for 1) i did: 0·2 + 1·4 + 2·4 + 3·x + 4·2 + 5·2 + 6·4 = total wins (=60) , so x =2 ..

#

is there a faster way ?

onyx glen
#

there's 20 teams total

#

2+4+4+2+2+4+x = 20

void jay
#

is there some kind of cue here? i was a bit skeptical to use the method you wrote because of the freq = 2 for 0 wins

#

i mean when would i count 2 and when wouldn't i count it if the other column shows a numerical value of 0

#

not sure if my question makes sense

onyx glen
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blissful girder
#

Hello! I'm curious, what does the bx term in the quadratic equation tells us about the graph?

If the leading term of the quadratic equation, ax, tells us about the shape of the parabola, while the coefficient tells us about the elevation of the graph in the y-axis... then what does bx tells us about the graph? What is the role of bx? This is my first question.

For the second question, please refer to the image attached. In this case, I am using x^2 - 2x + 1 as the equation. I deposited each term one by one on the Desmos app, and then I noticed that when I finally put -2x, the vertex shifts to -1. But the question is, why did it not shift to -2 if that's what I explicitly indicated? Why is it sitting there instead of -2? Does the roots of the graph influence the position of the vertex?

Thank you in advance!

cursive pier
#

ax not necessarily means what the shape is rather, the sign of a dictates if the parabola opens upwards or downward

#

in a very theoretical way, bx tells you the distance between two roots as well, larger the value the farther the two roots are

nimble ridge
blissful girder
#

They just tell you to apply the quadratic formulas to get the roots and then you move on with the next topic without telling you how did even those terms or equations come to life

nimble ridge
#

Factoring any quadratic expression w/ c=0 will reveal the two roots of the parabola and the x-coordinate of the vertex will be their average

blissful girder
#

Or what role do they even play lol

blissful girder
#

Why are we even equating everything to 0 in the first place thonk

#

Like we find the roots by equating it to 0, but why?

nimble ridge
#

Wish I could tell you more at the moment but I can't

blissful girder
#

Yeah, I'm sorry if I'm too demanding TvT

nimble ridge
#

They might explain stuff like this in greater detail in some college math classes when/if you get to that point but idk

cursive pier
# blissful girder Tell me more! I like this! They don't explain these stuff in school

hmm okay

  • a -> gives you as you said the shape
  • sign of a -> gives you direction of opening
  • b -> the size of gap between two roots
  • c -> as you said the y axis intercept

now you can just rearrange ax^2+bx+c = 0 into a(x-h)^2 = y - k

then you will see, (h,k) is just the position of the parabola head and r is just the shape.


and as for the needs, the simplest example of a parabola is maybe the glass inside a car's headlight and you need to understand where to put the bulb so that even with less power bulb you can get the most luminence and yada yada

blissful girder
blissful girder
nimble ridge
cursive pier
blissful girder
cursive pier
blissful girder
#

Thank you to @nimble ridge too!

blissful girder
scarlet pike
#

just slide these sliders to change the values of a,h,k and see how it changes the graph

blissful girder
#

Anyways, yes, this is very illuminating

cursive pier
stiff summit
#

I’ll just copy it here

stiff summit
#

might have noticed that the parabola will go through the same point on the y axis for any value of b

#

(if a and c are fixed)

#

this is because if you substitute x = 0, then y = ax^2 + bx + c = c, so the place where the parabola crosses the y-axis doesn't depend on b

#

next, since a doesn't change, the shape of the parabola (how wide it opens) doesn't change

#

so it's like you're sliding a rigid (you can imagine it as being glass), infinitely large, parabola up and down through that point on the y-axis, and keeping its direction the same

sonic stratus
#

between the three you can define any parabola.

#

parabolas of the form
ax^2 + c have inclination 0 at x = 0.
So they are all centered at the y-axis.

The inclination can move around the vertex.

blissful girder
#

Wait I replied to the wrong person lol

stiff summit
# blissful girder Like we find the roots by equating it to 0, but why?

on why you find the roots by setting y = 0: this is because y = 0 is the equation of the x-axis. So when you require both y = 0 and y = ax^2 + bx + c, in other words setting 0 = ax^2 + bx + c, you find the position of the intersection of the x-axis and the parabola, which is exactly where the two roots are

cursive pier
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also do not take so much stress, the more time passes and you come by new ideas and math these will automatically get more cleared, none of us cleared it overnight

stiff summit
full forumBOT
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@blissful girder Has your question been resolved?

blissful girder
# stiff summit on why you find the roots by setting y = 0: this is because y = 0 is the equatio...

I feel like my intuition is telling me to go higher... so I can stand on the summit and view everything else from the vantage point in order to get the big picture. There's a brick missing, but I can't pinpoint what. I am seeing something and nothing at the same time.

I think most of my inquiries are stemmed from a broader epistemic question as to why algebra is the way it is. Why is mathematics the way it is? Like, what's the point of doing all these things? (not alluding to something existential by the way) Why are we doing all these steps? Why are we factoring? Why are we equating to zero? Why do we have to add and subtract the two sides of the equation at the same time? Why are we doing this and that?

There is just something so utterly symmetrical about mathematics that I can't simply pinpoint as to where it is coming from...

And most importantly, what framework exactly is mathematics operating on? If philosophy uses reasoning, logic, dialectic, syllogisms... then what does mathematics utilizes?

I believe my epistemic inquiry has something to do with the mathematical tools besides abstraction. I'm only familiar with abstraction, I don't know yet about the others. I feel like my questions are eyeing on the study of mathematical structure. I'm not looking for formalisms, I'm looking for the lense as to how I can perceive mathematics.

It's really weird when you're standing at the negative space of things where both questions and answers simply don't exist yet, only a strange mix of intuition and vertigo. I'm sitting at the pre-formal edge of a framework that is quite elusive

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This feels like knowing how to move the pieces in chess but you don't know what to do because you don't have the tools, the strategy, the philosophy, and the way of properly thinking about it yet

stiff summit
stiff summit
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and then you learn some basic opening moves, and then you have a general direction of how a game goes

stiff summit
#

It is possible to build absolutely everything in maths up from undefined primitives and logic and axioms and definitions about various objects. It’s just that, beyond the undergraduate level, things get unwieldy, and you learn to fill in the details of the proof steps yourself, so you can make larger leaps and go farther

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but when you’re learning about quadratic equations, the focus is more on calculation and manipulation, because those tend to be the things that get applied most easily and clearly

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when you’re going shopping and have to calculate with discounts, you need to know how to calculate with percentages. If you’re calculating the path of a cannonball, or rates of reaction with two or more chemical species when they’re reaching equilibrium, or anything to do with parabolas, then it’s very useful to know how to translate a quadratic equation to and from general form, and vertex form, and find its roots, and so forth

full forumBOT
#
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stiff summit
#

that’s one of the goals of middle/high school maths, which is to give you tools you may not see the use of yet, but which you might be able to apply to something unexpected in future. So if you didn’t learn this stuff, then you would not know what you don’t know

#

.reopen

full forumBOT
blissful girder
# stiff summit maths uses logic, and can be based on set theory or type theory. You might want ...

Yeah, I think I should learn how to think about mathematics first, or how to think mathematically. This feels like I'm using a chopping board with the technique of a welder to cut vegetables, lol. I'm not the type of learner who will simply jump head-on into an abyss without knowing what happens on the other side, or someone who uses formulas blindly

I'm actually trying to teach myself calculus and I'm going back to algebra to treat some blind-spots. But right now, I had a realization. I realized that I don't want pre-requisites anymore, I want to know how to think about mathematics and how to think mathematically. I want to understand the rules of the game and not just follow it

stiff summit
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Interesting

blissful girder
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Why do we even have rules, how do these rules even come to exist thonk. I want to understand the rules so I can twist and break it eventually

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Those types of questions itch my brain

stiff summit
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You might like to try out the Natural Number Game, or maybe Reintroduction to Proofs

stiff summit
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(I decided that the answer was because, if you do the same thing to two equal things, then you end up with two equal things, and this is some kind of fundamental property of equality, maybe an axiom, but I didn’t think about it further until right now. For now I’d say that it can be taken as an axiom)

blissful girder
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I just bought a book

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Let me share the author

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Wait

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A Book of Abstract Algebra by Charles C. Pinter

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Is that good?

stiff summit
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Yes, some people recommend it

stiff summit
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I didn’t really read it because I had read another abstract algebra book by then

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But it looks fine from what I can tell

stiff summit
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it’s useful to have several books on one topic that you can reference

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you might be able to find a pdf of Herstein’s book online

stiff summit
stiff summit
blissful girder
#

By the way, can I ask you a question?

stiff summit
#

If you feel like that, maybe you could try real analysis, because that eventually leads to a justification of calculus and rigorous proofs for all the differentiation things, and, say, the Fundamental Theorem of Calculus

stiff summit
blissful girder
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Is it okay you confirm its veracity?

stiff summit
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what did it say?

#

seems a bit strange

blissful girder
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Sorry for the long string of images, lol

split hatch
#

category theory (the true summit)

stiff summit
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Mathematical thinkers don’t compute
they switch perspectives until the answer becomes unavoidable.

this is not true of several researchers. I’m not a researcher, but when I was thinking how to solve a certain problem which I didn’t know where to read about online (so I couldn’t really ask for help), I didn’t “switch perspectives until the answer became unavoidable”. I wrote down stuff I noticed until somehow I got some results and disproved my original guess. I’m guessing this is true of researchers, but with way more wrong turns and dead ends

blissful girder
#

GPT proposed group theory, is that adjacent to my trajectory?

stiff summit
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group theory is a part of abstract algebra

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it sounds like a crank

blissful girder
blissful girder
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I guess the way it talks says a lot about me

brittle sun
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What the fuck

stiff summit
wild sleet
#

Smiguel

maiden vapor
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what the blud

blissful girder
rare dock
#

what the blud

blissful girder
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What's up with the influx of people so suddenly

wild sleet
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his retribution, swift

stiff summit
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oh yeah there’s a bot command for this

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!nogpt

brittle sun
full forumBOT
#

Please do not trust ChatGPT or similar AI tools for mathematical tasks, as they often generate output which "sounds correct" but has numerous factual or logical errors. Use of these AI tools to answer other people's help questions is strictly against server rules (see #rules).

wild sleet
brittle sun
#

Either way, lemme read through the channel and engage with you in good faith

rare dock
blissful girder
rare dock
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it’s an honor to have your channel shared there

maiden vapor
#

honour*

rare dock
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pure you know i love you but you’re wrong on this one

blissful girder
#

.close

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#
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full forumBOT
#
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patent crow
#

For 12b how would I be able to graph this?? Graph each transformation?

slate violet
rigid crescent
#

graph log(x) and log(10nx) with some n

patent crow
#

Okay so I set an arbitrary amount for n?

slate violet
#

or for logarithms you can use log rules to simplify that to log(10n) + log(x)

patent crow
#

Like n = 1?

slate violet
#

if that helps you, sure

patent crow
glossy valveBOT
slate violet
#

yeah, you should know what adding some constant to a function does to the graph

patent crow
#

Okay thanks guys! Appreciate it

slate violet
#

no worries!

patent crow
#

.close

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#
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full forumBOT
#
Available help channel!

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Show your work, and if possible, explain where you are stuck.
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waxen raven
#

take $D = {(x,y) \in \mathbb{R}^2 | x^2 + y^2 \leq 1}$
\\
$$f: D \rightarrow R$$
$$\ (x,y) \mapsto x^2 + xy + y^2$$
\\
Find all extremum points of $f$.

waxen raven
#

could someone please help me out with this?

glossy valveBOT
#

Moonful

spiral vigil
#

find all relative extrema on the interior and then on the boundary

waxen raven
#

sorry i couldnt do curly brackets

waxen raven
#

now how do i know if it's a maxima or minima

spiral vigil
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\cap for intersection

waxen raven
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ah

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sorry how do i do curly brackets 😭 😭

spiral vigil
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backslash i think? \{

glossy valveBOT
#

Moonful

waxen raven
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ah thank you!

#

ok so that

#

now how do i know if it's a maxima orminima

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sorry E is the set of extremum points of f

spiral vigil
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two options -- use the second derivative with the like matrix determinant thingo

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or just pick a point very very near it and check xD

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second derivative is much more reliable

waxen raven
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i believe the hessian matrix yields a 0 eigenvalue

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i can try 1 sc

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sec

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oh never mind!

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it got positive eigenvalues so minima

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the plan was for it to get a 0 eigenvalue so then i'd be like "how do i know if its max or min" 😭

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ok lets say it did get a 0 eigenvalue, what would i do?

spiral vigil
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it would be neither a max nor a min

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think of f(x) = x^3

waxen raven
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its a saddle point if one eigenvalue is positive and the other negative

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but the test is inconclusive if an eigenvalue is 0

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so what do i do when theres a 0 eigenvalue 😭 😭

spiral vigil
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apparently that means it's flat

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(or sloped)

waxen raven
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sloped?

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/flat?

spiral vigil
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like a ramp

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but if you're only looking at spots where f ' = 0 then it'll be flat

waxen raven
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so like z = x^2?

spiral vigil
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no... more like z = 0

waxen raven
spiral vigil
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or z = x + y

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oh

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right two dim

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yes

waxen raven
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ah let me see

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ohh

spiral vigil
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actually yeah go ahead and check

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for z = x^2 i'm curious

waxen raven
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well z=x^2 when you set gradient to 0 you get x=0 and y E R

spiral vigil
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no yeah it'll have a 0 eigenvector which makes sense since the surface is not curved

waxen raven
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hmmmm i see

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so does this not count as a max or min?

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also now looking at boundary

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(2) $E \cap \partial D$
$$\text{Define } \varphi : [0, 2\pi ) \rightarrow \mathbb{R}^2$$
$$ t \mapsto (\cos t, \sin t)$$

We know that on $\partial D$, $(x,y) = \varphi (t)$. We want $f(x,y)$.

Hence,
$$f(x,y) = f(\varphi (t)) = f(\cos t, \sin t) = 1 + \frac{1}{2} \sin 2t$$

Now define
$$g: [0, 2\pi ) \rightarrow \mathbb{R}$$
$$ t \mapsto 1 + \frac{1}{2} \sin 2t$$

what do i do from here?

glossy valveBOT
#

Moonful

waxen raven
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actually, i know that we have to solve g'(t) = 0

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but im confused how we just transformed f (which was a 2d problem) into a one dimensional problem

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yes i know we used polar corrdinates by letting x=cos(t) and y=sin(t)