Question

Find the derivative of f(x) = -cos (2x^2-3)

Answer 1

Do you know how to use the chain rule?

Answer 2

yeah yes i do

Answer 3

Well your inner function is \(2x^2-3\) and your outer function is \(-\cos(x)\). There shouldn't be anything hard about this.

Answer 4

do we have to use chain rule ? i'm confused on what we should do when with the -cos

Answer 5

The - is just \(-1\cdot \cos(x)\). It's a constant. You can pull it out and put it back in after.

Answer 6

oh really? but this have to use f(x+h)-f(x) first derivation ..

Answer 7

You have to use this you mean? \[\Large \lim_{h\rightarrow 0}\frac{f(x+h)-f(x)}{h}\]

Answer 8

You're not allowed to use the chain rule?

Answer 9

Oh sorry, i just realised it only has to use chain rule. I make things go more complicated -_-

Answer 10

So can you do it now?

Answer 11

yeah the answer is sin(2x^2-3)(4x) right ?

Answer 12

yeah, i agree that

Answer 13

Oh thank you so much :D

Answer 14

It's correct.