Use the Power-Reducing Formulas
- $\cos ^ { 4 } x$

Multiple Choice

Use the Power-Reducing Formulas
- $\cos ^ { 4 } x$

A) $\frac { 3 + 4 \cos 2 x + \cos 4 x } { 8 }$
B) $\frac { 3 + 2 \cos 2 x + \cos 4 x } { 8 }$
C) $\frac { 3 - 4 \cos 2 x + \cos 4 x } { 8 }$
D) $\frac { 2 - 4 \cos 2 x + \cos 4 x } { 8 }$