Use Sum and Difference Formulas for Cosines and Sines
- $\cos 15 ^ { \circ } \cos 45 ^ { \circ } - \sin 15 ^ { \circ } \sin 45 ^ { \circ }$

Multiple Choice

Use Sum and Difference Formulas for Cosines and Sines
- $\cos 15 ^ { \circ } \cos 45 ^ { \circ } - \sin 15 ^ { \circ } \sin 45 ^ { \circ }$

A) $\frac { 1 } { 2 }$
B) $\frac { \sqrt { 3 } } { 2 }$
C) $\frac { 1 } { 4 }$
D) $\sqrt { 3 }$