Use Integration by Parts to Establish a Reduction Formula for the Integral

Multiple Choice

Use integration by parts to establish a reduction formula for the integral.
- $$\int \cos ^ { n } x d x$$

A) $\int \cos ^ { n } x d x = \cos ^ { n - 1 } x \sin x - ( n - 1 ) \int \sin x \cos ^ { n - 2 } x d x$
B) $\int \cos ^ { n } x d x = - \cos ^ { n - 1 } x \sin x + ( n - 1 ) \int \cos ^ { n - 2 } x d x$
C) $\int \cos ^ { n } x d x = \frac { 1 } { n } \cos ^ { n - 1 } x \sin x + \frac { n - 1 } { n } \int \cos ^ { n - 2 } x d x$
D) $\int \cos ^ { n } x d x = \frac { 1 } { n } \cos ^ { n - 1 } x \sin x - \frac { n - 1 } { n } \int \cos ^ { n - 1 } x d x$