Solve the Equation (X in Radians And $$\boldsymbol { \theta }$$

Solve the equation (x in radians and $$\boldsymbol { \theta }$$ in degrees) for all exact solutions where appropriate. Round approximate answers
in radians to four decimal places and approximate answers in degrees to the nearest tenth.
- $$\cos ^ { 2 } x - 1 = 0$$

A) $\left\{ \frac { \pi } { 3 } + n \pi \right\}$
B) $\left\{ \frac { \pi } { 2 } + 2 n \pi \right\}$
C) $\{ 2 n \pi \}$
D) $\{ n \pi \}$