ebonyscythe, I think you have an error in the limits of your first integral:
$\displaystyle u = \cos x$, so when x=0, $\displaystyle u = \cos (0) = 1$, and so your first integral should be $\displaystyle -\int_{1}^{-1} u^2*du$, not $\displaystyle -\int_{0}^{-1} u^2*du$.
--Kevin C.