How do you find the integral of (23x)cosxdx?

1 Answer
Apr 17, 2018

(23x)sinx3cosx+C

Explanation:

We have:

(23x)cosxdx

The integration by parts states that:

udv=uvvdu

We let:

u=23x

dv=cosx

du=ddx(23x)

du=3

v=cosxdx

v=sinx

We now have:

(23x)sinxsinx3dx

(23x)sinx+3sinxdx

Remember that:

sinxdx=cosx

(23x)sinx+3cosx

(23x)sinx3cosx

Do you C why this is incomplete?

(23x)sinx3cosx+C

That is the answer!Just note that my way of solving is the simplest, but not the only solution.