Use Identities to Find the Indicated Value for Each Angle $2 \cos ^ { 2 } 22.5 ^ { \circ } - 1$

Multiple Choice

Use identities to find the indicated value for each angle measure.
- $2 \cos ^ { 2 } 22.5 ^ { \circ } - 1$

A) $\frac { \sqrt { 2 } } { 2 }$
B) $\frac { \sqrt { 3 } } { 3 }$
C) $\sqrt { 3 }$
D) $\frac { \sqrt { 2 } } { 4 }$