For the Graph of a Circular Function Y = F(x) $\cos ^ { 2 } 4 x - \sin ^ { 2 } 4 x$

Multiple Choice

For the graph of a circular function y = f(x) , determine whether f(-x) = f(x) or f(-x) = -f(x) is true.
- $\cos ^ { 2 } 4 x - \sin ^ { 2 } 4 x$

A) $\cos 4 x$
B) $2 \sin 4 x$
C) $\frac { 1 } { 2 } \sin 16 x$
D) $\cos 8 x$