zurf
Find the derivative of f(x) = cos (2x^23)



This Question is Closed

wio
Best Response
You've already chosen the best response.
0
Do you know how to use the chain rule?

zurf
Best Response
You've already chosen the best response.
0
yeah yes i do

wio
Best Response
You've already chosen the best response.
0
Well your inner function is \(2x^23\) and your outer function is \(\cos(x)\). There shouldn't be anything hard about this.

zurf
Best Response
You've already chosen the best response.
0
do we have to use chain rule ? i'm confused on what we should do when with the cos

wio
Best Response
You've already chosen the best response.
0
The  is just \(1\cdot \cos(x)\). It's a constant. You can pull it out and put it back in after.

zurf
Best Response
You've already chosen the best response.
0
oh really? but this have to use f(x+h)f(x) first derivation ..

wio
Best Response
You've already chosen the best response.
0
You have to use this you mean? \[\Large \lim_{h\rightarrow 0}\frac{f(x+h)f(x)}{h}\]

wio
Best Response
You've already chosen the best response.
0
You're not allowed to use the chain rule?

zurf
Best Response
You've already chosen the best response.
0
Oh sorry, i just realised it only has to use chain rule. I make things go more complicated _

wio
Best Response
You've already chosen the best response.
0
So can you do it now?

zurf
Best Response
You've already chosen the best response.
0
yeah the answer is sin(2x^23)(4x) right ?

RadEn
Best Response
You've already chosen the best response.
0
yeah, i agree that

zurf
Best Response
You've already chosen the best response.
0
Oh thank you so much :D

wio
Best Response
You've already chosen the best response.
0
It's correct.