How do you integrate sin(x)3cos(x)dx?

1 Answer
May 1, 2016

Use a u-substitution to get sin3xcosxdx=sin4x4+C.

Explanation:

What we have in this integral is a function, sinx, and its derivative, cosx. That means the integral is solvable using a u-substitution:
Let u=sinxdudx=cosxdu=cosxdx
With this substitution, sin3xcosxdx becomes:
u3du

This new integral is easily evaluated using the reverse power rule:
u3du=u3+13+1+C=u44+C

Because u=sinx, we can substitute to get a final answer of:
sin3xcosxdx=sin4x4+C