Find All Solutions in the Interval [0, 2π) $\cos ^ { 2 } \left( \frac { x } { 2 } \right) = \cos ^ { 2 } x$

Multiple Choice

Find all solutions in the interval [0, 2π) .
- $\cos ^ { 2 } \left( \frac { x } { 2 } \right) = \cos ^ { 2 } x$

A) $0 , \frac { 2 \pi } { 3 } , \frac { 4 \pi } { 3 }$
B) $0 , \frac { 2 \pi } { 3 }$
C) $\frac { \pi } { 6 } , \pi , \frac { 11 \pi } { 6 }$
D) $0 , \frac { \pi } { 6 }$