How may I derive this equation?

[staka]

How may I derive y=cos^3(sinx)?
I thought simply just y=3cos(sinx)^2(cosx)...

Answer given is -3cosxsin(sinx)cos^2(sinx) but no idea how to get to that.

 

[C.E]

I am a bit confused about what the exact question is. What is it?

 

[staka]

How to derive the function: y=cos^3(sinx) is my question... solving for y'=.

 

[Mark44]

I think you didn't use the chain rule enough times.
You need the derivative of cos³(sin(x)) with respect to cos(sin(x)) times the derivative of cos(sin(x)) wrt sin(x) times the derivative of sin(x) wrt x.

 

[cristo]

By derive you mean differentiate, right?

Try writing t=sinx, then y=[cos(t)]^3. Then, dy/dx=(dy/dt)(dt/dx). Course, you need to use the chain rule again when differentiating y wrt t.

 

[staka]

Alright. I'll retry.. solving.

 

[C.E]

Oh, differentiate now I know what you are trying to do. Are you familiar with the chain rule?

 

[staka]

I am familar with the chain rule.. I'll retry.

 

[staka]

Alright thanks. I've solved it correctly.