#Calculus

311 messages · Page 1 of 1 (latest)

neat granite
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how to solve pliz help

inner salmonBOT
soft crypt
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wym how to solve ?

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it's just computing derivatives

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(although there's smarter ways than others here)

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@neat granite

neat granite
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yeah i basically need that smarter way

soft crypt
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do you have an answer already

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even if it's not found in a smart way

soft crypt
neat granite
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bro i can't get u

soft crypt
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d(u^2)/dx = 2 u * du/dx is my point

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same for v

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so u * du/dx = 1/2 d(u^2)/dx

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turns out that simplifies a whole lot of stuff here

neat granite
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can u pliz show me?

soft crypt
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show what ?

neat granite
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i did till second order derivative but not able to get the answer

neat granite
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in a paper coz i can't get u

soft crypt
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$$\dv{(u^2)}{x} = u \dv{u}{x} + \dv{u}{x} u = 2u\dv{u}{x}$$

neat cargoBOT
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aPlatypus

soft crypt
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@neat granite

neat granite
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bro is dis a formula?

soft crypt
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yeah

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it's just product rule

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u^2 = u * u

neat granite
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oh i c

soft crypt
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so $u\dv{u}{x} = \frac12 \dv{(u^2)}{x}$

neat cargoBOT
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aPlatypus

soft crypt
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same for $v$, $v\dv{v}{x} = \frac12 \dv{(v^2)}{x}$

neat cargoBOT
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aPlatypus

soft crypt
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try and add those

neat granite
soft crypt
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sure

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let's just finish the first though

neat granite
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ok

soft crypt
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@neat granite

neat granite
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got stucked at 1 step

soft crypt
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yeah?

neat granite
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Wt to do after dis?

soft crypt
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you don't have to compute them seperately

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alright I'll spell it out completely for you

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\begin{align*}
u\dv{u}{x} + v\dv{v}{x} &= \frac12 \dv{(u^2)}{x} + \frac12 \dv{(v^2)}{x} \\
&= \frac12 \dv{(u^2 + v^2)}{x}
\end{align*}
neat cargoBOT
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aPlatypus

soft crypt
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that 2nd line works cause the derivative is a linear operator

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df/dx + dg/dx = d(f+g)/dx

neat granite
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bro can we do coding here?

soft crypt
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nah this bot is only a thing that types math

neat granite
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oh

soft crypt
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now u^2 + v^2 is easy to work with

neat granite
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still need to use uv form ryt?

soft crypt
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it's just e^(2ax)

neat granite
soft crypt
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no

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u^2 + v^2 is e^(2ax)

neat granite
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Formula?

soft crypt
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no?

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literally from the functions you are given

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but I mean honestly if you have trouble with your algebra, I'd focus on getting better at algebra before using fancy tricks like I'm doing here

neat granite
soft crypt
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if your algebra is already shaky, you just won't notice the trick

soft crypt
neat granite
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it should be 2e^2ax ryt?

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as sin^2bx+cos^2bx gives 1

soft crypt
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nope

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e^(2ax) cos^2(bx) + e^(2ax) sin^2(bx) = e^(2ax) * (cos^2(bx) + sin^2(bx)) = e^(2ax) * 1

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algebra again mate

neat granite
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bro i can't get that step

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did u jump any step?

soft crypt
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it's just factoring

neat granite
soft crypt
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I'm not even talking about the derivative yet

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just u^2 + v^2

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@neat granite

neat granite
soft crypt
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wdym ?

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no I'm not using product rule

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just straight up algebra

neat granite
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ok got it

soft crypt
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alright so u^2 + v^2 = e^(2ax)

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that's quite easy to find the derivative of that

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\begin{align*}
u\dv{u}{x} + v\dv{v}{x} &= \frac12 \dv{(u^2)}{x} + \frac12 \dv{(v^2)}{x} \\
&= \frac12 \dv{(u^2 + v^2)}{x} \\
&= \frac12 2ae^{2ax} \\
&= ae^{2ax}
\end{align*}
neat granite
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got it bro

neat cargoBOT
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aPlatypus

neat granite
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thanks a lot

soft crypt
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but yeah get your algebra straight though

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you won't have me for your test

neat granite
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u just said algebra so i was wondering where did the functions go

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but u used trigo too

soft crypt
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if your algebra isn't perfectly fine, you won't notice those tricks

neat granite
soft crypt
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khan academy is prolly fine

neat granite
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i did till second order derivative but not able to get the answer

soft crypt
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yeah what are the derivatives you got ?

neat granite
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xy' = cos(logx)

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xy''={-sin(logx)}/x

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where r u from btw bro?

soft crypt
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europe

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your derivatives are fine

neat granite
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cool bro

soft crypt
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that question seems screwed up indeed

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if anything x^2 d^2y/dx^2 + y = 0 works

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,w solve y'' + y = 0

soft crypt
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,w solve y'' = 0

soft crypt
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,w solve x^2y'' + xy' + y = 0

soft crypt
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oops, should have talked more slowly I guess

neat granite
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y bro

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sorry if i did anything wrong i'm new to discord

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bro u there?

soft crypt
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yeah

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your second derivative doesn't work now that I think about it

neat granite
soft crypt
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xy' = cos(logx)
xy''={-sin(logx)}/x
the 2nd one doesn't follow from the first

neat granite
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it does bro

soft crypt
soft crypt
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you differentiated both sides

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however on the right side there's a product of two functions

neat granite
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y' is {cos(logx)}/x

soft crypt
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ok sure

neat granite
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now to differentiate again i took x to left hand side

soft crypt
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you can just differentiate like that

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but ok you can try by putting x to the LHS

neat granite
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how bro

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quotient rule?

soft crypt
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yes

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your way isn't bad either

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you screwed up the execution that's all

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xy' = cos(log(x))

neat granite
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i did according to options😭

soft crypt
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so d/dx (xy') = d/dx (cos(log(x)))

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on the right you get -sin(log(x))/x indeed

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on the left you have a product of two functions

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xy'' + y' = -sin(log(x))/x

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x^2 y'' + xy' = -sin(log(x))

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that's a valid deduction

neat granite
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bro in quotient rule i think it went more hectic

soft crypt
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yeah it's a bit harder

soft crypt
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so x^2 y'' + xy' + y = -sin(log(x)) + sin(log(x)) = 0

neat granite
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ohh

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so wt to do from here bro

soft crypt
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your 4th line is wrong

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that's what I've been saying for the past 10 minutes

neat granite
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how bro

soft crypt
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xy' is a product of two functions

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you can't just say the derivative of xy' is xy''

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as attractive as it sounds

neat granite
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in the option they gave this way only ryt?

soft crypt
soft crypt
neat granite
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the option c

soft crypt
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if you do a wrong step you'll get fucked up results that's all I'm saying

neat granite
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bro literally i'm not getting ur steps

soft crypt
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you won't get option c with the way you've done it

neat granite
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can u pliz use pen and paper?

soft crypt
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$$\dv{(xy')}{x} = \dv{x}{x}y' + x\dv{(y')}{x} = y' + xy''$$

neat cargoBOT
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aPlatypus

soft crypt
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product rule

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@neat granite

neat granite
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hmm let me try to work it out once now

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are these correct?

soft crypt
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$$\dv{(xy')}{x} = \cos(\log(x)) - \sin(\log(x))$$

neat cargoBOT
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aPlatypus

soft crypt
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yes that's true

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your notations are completely wtf though

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but it seems like you got it

neat granite
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wt to do after these now

neat granite
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but i was solving y'' only ryt?

soft crypt
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wait nvm

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xy' is already cos(log(x))

echo fern
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want me to continue? @soft crypt

soft crypt
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ig

neat granite
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i'm ok with that too

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y'' ki baat ho rahi hai bhai

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haan

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hmm

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hm

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haan

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wahi pe product rule lagaya

neat granite
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lhs and rhs ko alag se calculate karni hai?

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dekho jo mera y' hai wo cos(log(x)) hai na?

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to maine x*cos(log(x))/x kiya

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kyu ki wahi mera y' tha

neat cargoBOT
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Dissrupt

neat granite
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yes

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bhai ek paper notebook mai samjhado na

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oo

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abhi tak to aya

neat granite
neat granite
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Bhai sorry internet server down ho gaya tha

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@echo fern kya tum ho?

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Fir ye aaya

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Bhai dy/dx cos{log(x)} /x aya ryt

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Fir x ko left hand side bhej diya

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X*dy/dx=x cos{log(x)} ryt?

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Kyu ki mere dy/dx hi toh cos( log( x)/x hai

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Bhai come straight to the point

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Kaha galti kiya wo batao

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Wiase tum kaha se ho bhai

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Itna badiya hindi bol rahe ho

neat cargoBOT
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Dissrupt

neat granite
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Haan yehi toh maine bhi kiya tha

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Matlab(a+b) ²= a²+b²+2ab aisa nahi hai ye

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Rhs lhs ka result nahi dega?

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Wo toh maine bas example diya tha identity ka

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Like rhs is not the result of lhs ye kehna chahte ho ryt?

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Y kya hai?

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Y =Sin (log(x)) na?

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Bhai maine kaha galti kiya wo step batao na

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Y ka value put nahi karna hai?

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Ok in general ki baat kar rahe ho

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Like derivative of dy/dx is d²y/dx²?

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1 ayega

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Okok

neat cargoBOT
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Dissrupt

neat granite
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Abhi rhs ko bhi alag se differentiate karna hai?

neat granite
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Product rule rhs mai bhi?

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Rhs ka equation batana ekbar

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Den - sin(log(x) /x

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Sahi hai?

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X²d²y/dx² +xdy/dx=- sin(log(x)?

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Sin (log(x))

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Lhs jane se y ban jayega ok

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Got it

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Thansk a lot

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Haan bhai

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Kaha se ho tum?

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Maine bich se hi options ke saath match karne ki koshis ki isliye

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Konsi state?

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Achi baat hai Indian bhi calculus chat mai hi kr pa rahe hai

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Bhai wo dusra bhai jo tha wo tumhara dost hai?

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Tum phone nahi chalate?

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Konsi class mai ho tum?

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Oo cbse?

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Pass out iss saal

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Lekin bas naam ka

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11 aur 12 covid mai chala gaya

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Nah

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Lekin manipur mai violence ho raha hai na

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Isliye dadi ke ghar mai baitha hu

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Algebra strong karo bol raha tha woh bhai

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Kya chij strong karna hai exactly

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Tumse pahele jo mukhe sikha raha tha

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Haan

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Yes

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Lekin ab realise huwa 12 ka 20% bhi cover nahi kya hamare time mai

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Nahi manipur mai hi jaakr karunga

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Waise distance course lene ka soch raha hu

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Abhi toh mere pass kitan nahi hai 11 ka

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Pata nahi jo option milega usi ka lelunga bas degree ke liye

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Toh kaha se padu bhai?

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Waise woh derivative bot ko chalana sikha do na

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Integration bhi hoga usse?

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Kaha se?

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Youtube pe nahi milenge?

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Waise ncert se nahi toh kaha se padu?

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Yehi bots ko chalane ka tarika

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Konsi channel se?

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Latex matlab?

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Aaj hi naam sun rahu hu bhai

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Famous nahi hai woh?

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Lekin mai jee ke liye preparation nahi kar rahu hu

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Wahi basic hi hila hai bhai

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Corona ke time mai 11 ka pura online hi huwa

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Aur 12 mai bhi maths maam ne school lately join kiya

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Integration ka out of 11 exercise bas 5 the

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Yh?

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Oh yt bolo na

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Ok

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Thanks bhai

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Abhi nda ka pyqs tha wo question

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Ohh

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Maine first time encounter kiya

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Like jo general derivative hai us ka question aj tak nahi kiya tha

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Isliye kuch nahi samaj mai ah raha tha

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Oh

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Bas 1 months baki hai ab🥶

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Nda sept 3 ko hai

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Isliye to pyqs kar raha tha

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11th?

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Sukriya

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Nah nah nahi karunga

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Abhi toh bas pyqs hi karta jaunga

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Kaha pe?

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.solved

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Oo

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Acha case sensitive hai🤣

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Ho gaya?

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.solved

inner salmonBOT
#
Solved

Post marked as solved by @neat granite.

Use .unsolved if this was a mistake.

neat granite
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Ok itna advanced badiya

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@soft crypt how shall i search algebra basics or algebra for calculus?

soft crypt
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if you want a book, there's basic mathematics by serge lang which is quite alright for that (findable online not too difficultly)

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if you prefer online, review the algebra part in khan academy, at least you have an infinite source of exercises there (although repetitive)

neat granite
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Algebra covers exponents and?

soft crypt
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I just put basic computation in algebra in my head (i'm a bit old lol)

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I guess precalculus would be more fitting to your needs rn

neat granite
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Wts precalculus?

soft crypt
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In mathematics education, precalculus is a course, or a set of courses, that includes algebra and trigonometry at a level which is designed to prepare students for the study of calculus, thus the name precalculus. Schools often distinguish between algebra and trigonometry as two separate parts of the coursework.

neat granite
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I'm ok with trigo

soft crypt
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it's a bit of a melting pot of algebra and common functions (trig, log, exponential, ...non-exhaustive list)

neat granite
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Oh