Primitive of Power of x by Cosine of a x/Corollary

Theorem

 * $\displaystyle \int x^m \cos a x \rd x = \sum_{k \mathop = 1}^{m+1} \paren {m^{\underline {k-1}} \frac {x^{m+1-k}} {a^k} \map {\sin} {x + \dfrac {\pi} 2 \paren {k-1}} }$