What is the derivative of y=cos^4(x^2)?

1 Answer
Sep 2, 2016

-8 x cos x cos ^2 x^2 sin x^2

Explanation:

Using the quotient rule:

d/dx cos ^ 4 x^ 2= 2 cos^2 x^2 d/dx cos ^ 2 x^ 2

further:

= 2 * cos ^ 2( x^ 2) {2 * cos x d/dx cos x^ 2 }

now applying the chain rule we get :

= -8 x cos x cos ^2 x^2 sin x^2