How do you find the antiderivative of int (x^3sinx) dx?

1 Answer
Oct 16, 2016

= - x^3 cos x + 3x^2 sin x + 6x cos x - 6 sin x + C

Explanation:

int x^3 sin x dx

= int x^3 (-cos x)^prime dx

= - x^3 cos x + int (x^3)^prime cos xdx

= - x^3 cos x + int 3x^2 cos xdx

= - x^3 cos x + int 3x^2 (sin x)^prime dx

= - x^3 cos x + ( 3x^2 sin x - int (3x^2)^prime sin x dx )

= - x^3 cos x + 3x^2 sin x - int 6x sin x dx

= - x^3 cos x + 3x^2 sin x - int 6x (- cos x)^prime dx

= - x^3 cos x + 3x^2 sin x - ( - 6x cos x + int (6x)^prime cos xdx )

= - x^3 cos x + 3x^2 sin x + 6x cos x - int 6 cos xdx

= - x^3 cos x + 3x^2 sin x + 6x cos x - 6 sin x + C