anyone understand this, its IB math hl

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i’m here for help

@robust scaffold

you re stuck at what question?

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how do i create a channel?

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nvm

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the whole thing i dont get

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did you do physics?

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yeah

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so you have v a function and E another function which is equal to 3v^2

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yeah i thought of putting the value of v(T) into E(V)

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you know that v(t) = 2 cos(t)

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yes

that way you get E(t)

instead of E(v)

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is it 3(cos(t))^2

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there’s a 2 missing i guess

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wdym the power?

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no v = 2 cos(t)

so v^2 = …

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idk man

what do u substitute into what

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imagine x= 3 times 5

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x^2 = (3 times 5)^2 = (3^2) times (5^2)

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yes this is it

question 1 is done

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dab

thanks

now question 2

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now you have to derive what you found

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do i use product rule

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use whatever you like

i want to teach you how to fail and learn from your mistakes

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first mistake :

when you derive a cos(x)

you get ….

@robust scaffold

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but its just a cos

not a cosine

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cosine is the full name of cos

anyways

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its a -sin

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yes

you wrote v’= …

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so its -sin^2t

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no

(cos(x)^2 )’ = -2 sin(x)cos(x)

here’s the proof:

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so is it -2sin(t)

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(cos(t) x cos(t) )’ = -sin(t)xcos(t) - cos(t)xsin(t) = -2cos(t)xsint(t)

are you still with me ?

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yh is this the product rule

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yeah

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wait give me a min

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you normally use the product rule with functions and not constants like 12 or 23 or 50

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this is about cosine or its related to the question

sorry im dumb af

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it is related because you should derive cos^2(t) to derive E

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so why are u deriving cos(t) instead of cos^2(t) in the question

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you mean here ?

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yeah

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cos(t) x cos(t) = cos^2(t)

the little x is times

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doesnt it become cos^2(t)^2

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ohh

no

cos^2(t) = cos(t)^2 it’s just a different notation

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oh ok

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BUT!!!! it’s not the same as cos(t^2)

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but if you multiply cos(t) with itself dont u get that

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yes

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if you square it

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the idea of squaring is to multiply the same thing by itself

so 2^2 = 2x2= 4

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i know but doesnt it give cos^2(t)^2

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cos x cos = cos^2

cos(t)^2 = cos^2(t)

cos^2(t)^2 doesn’t make sense because you’re using two notation to signify the same thing at the same time

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whats sin x sin

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sin^2

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my bad looooool

so the answer is -sin^2(t)

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not even close

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eeshh

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derive me this : cos(t) x cos(t)

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cos^2(t)

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yeah derive it

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2cos(t)

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no

again

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-2sin(t)

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no

again

write it down

you have 2 minutes

or i’m gone

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geez

ok

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times up

what you got ?

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let me show u what i got

its the same thing

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use the product rule

on the cos(t) x cos(t)

do it one more time

30 secondes

times up

show me what you did @robust scaffold

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perfect

so you got -2 cos(t)sin(t)

that’s it

for question 2

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how is it -2cos(t)

wait i think i got it

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i’m gonna leave you here, it’s 1:44 am for me

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ok thanks for all the help fr

but u multiply with 12 ryt

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but here’s how you should do question 3: - you should find t so when you plug this t in E’ you get 4 and there you have the answer

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yes

good bye

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so t is 4

bet bye

thanks allat

[tough pulsar]

.close