Question

how do you know when to use chain rule

Answer 1

when the terms are functions (instead of just a single x)

Answer 2

for example

\[x^2\]
^don't use chain rule
\[(1-x^2)^2\]
^use chain rule

Answer 3

here's another example
\[\frac 1x\]
^don't use chain rule
\[\frac 1 {1-x}\]
^use chain rule

Answer 4

you should get the correct answer even if you use chain rule when unnecessary.

Answer 5

but yeah, what they said as well

Answer 6

there's really no "unnecessary" in chain rule..chain rule is always used

Answer 7

ok so how would i do v(x)=cos3x/2

Answer 8

is that \[\frac {\cos (3x)}{2}\]
or
\[\cos (\frac{3x}2)\]

Answer 9

the second

Answer 10

this uses chain rule (because x has a coefficient. it's not a single x anymore)

Answer 11

ok i got as far as -sin 3x/2theni go
t stuck

Answer 12

that's right. now take the derivative of 3x/2

Answer 13

why 3x/2

Answer 14

because it has an x....

Answer 15

...i think that's a wrong way to describe it...but the idea is pretty much you differentiate the x.

Answer 16

let me think of a better way to describe it....

Answer 17

here's one

\[\cos (\frac {3x}2)\]
think of 3x/2 as u

so you have
\[\cos u\]
now, you take the derivative of this
\[-\sin u\]
but according tochain rule, you multiply it to the derivative of u too
\[-\sin u \text du\]
where du is the derivative of u

is that easier to understand?

Answer 18

oh ok got it!!!!

Answer 19

wonderful

Answer 20

it's great if you understand that method...because trust me, you'll use that kind of method in a more advanced branch of calculus

Answer 21

yeah i know does it get easier as you move one in calculus cuz im struggling!!!

Answer 22

that depends if you're in an online school...because online schools teach topics randomly

but if you're in a regular school... calculus gets harder...and then easier...but as long as you know the basics of diff cal, then you can survive

Answer 23

try and read this...it might be helpful http://openstudy.com/study#/updates/504b49a7e4b0985a7a58a1a7