How do you find the derivative of y= sin{cos^2(tanx)}?

1 Answer
Nov 8, 2017

(dy)/(dx)=-2sec^2(x)sin(tanx)cos(tanx)cos(cos^2(tan(x)))

Explanation:

y= sin(cos^2(tanx))=sin(f(x))

y=sin(f(x))=>(dy)/(dx)=f'(x)cos(f(x))

f(x)=cos^2(g(x))=(cos(g(x)))^2
f'(x)=2*d/(dx)[cos(g(x))] * cos(g(x))
f'(x)=2*-g'(x)sin(g(x))*cos(g(x))
f'(x)=-2g'(x)sin(g(x))cos(g(x))

g(x)=tanx
g'(x)=sec^2x

Therefore, f'(x)=-2sec^2(x)sin(tanx)cos(tanx)

(dy)/(dx)=-2sec^2(x)sin(tanx)cos(tanx)cos(cos^2(tan(x)))