∫4(f(x))^3 f'(x)dx equals :

Question

∫4(f(x))^3 f'(x)dx equals :

a) (f'(x))^4 + C

b) (f(x))^4 +C

c) (f(x))^3 +C

Answer 1

The answer is b.

if u=f(x), the the integrand becomes u³ du.