Solutions

a) We have that $f'(x)=3x^2$. You simply need to plug in numbers.

b) Same answer as in a).

c)

$$f'(a^2)=3(a^2)^2,\qquad f'(x^2)=3(x^2)^2.$$

d)

$$g'(x)=\frac{d(x^2)^3}{dx}=6x^5,\qquad f'(x^2)=3x^4.$$