How do you differentiate y =x /sec ^2x^3 using the chain rule?

1 Answer
Jul 4, 2018

(dy)/(dx)=cosx^3[cosx^3-6x^3sinx^3]

Explanation:

Here,

y=x/sec^2(x^3)

=>y=x*cos^2(x^3)

Diff.w.r.t. x , using Product rule and Chain Rule:

(dy)/(dx)=x*d/(dx)(cos^2x^3)+cos^2x^3*d/(dx)(x)

=>(dy)/(dx)=x*2cosx^3(-sinx^3)d/(dx)(x^3)+cos^2x^3*1

=>(dy)/(dx)=-2xsinx^3cosx^3*3x^2+cos^2x^3

=>(dy)/(dx)=-6x^3sinx^3cosx^3+cos^2x^3

=>(dy)/(dx)=cos^2x^3-6x^3sinx^3cosx^3...to(1)

=>(dy)/(dx)=cosx^3[cosx^3-6x^3sinx^3]

Note :

From (1) we can simplify in the form :

(dy)/(dx)=cos^2x^3-6x^3sinx^3cosx^3

=>(dy)/(dx)=cos^2x^3-3x^3{2sinx^3cosx^3}

=>(dy)/(dx)=cos^2x^3-3x^3*sin2(x^3)