Ok, i worked through a problem and got my answer which was wrong, so i checked the solution and i dont understand the last step:

:integration: 1/8 (1 - cos(2x) - cos^2(2x) +cos^3(2x)dx

=1/16x - 1/64sin(4x) - 1/48sin^3(2x) + C

Needless to say, i integrated the same thing and got something different, i tried differentiating the final answer in order to see what i should do, but nothing work for my feeble simian mind.