\sin ^2 (x) = \frac{1}{2} \sin (x) = - \sqrt {\frac{1}{2}} of \sin (x) = \sqrt {\frac{1}{2}} \sin (x) = - \frac{1}{2}\sqrt 2 of \sin (x) = \frac{1}{2}\sqrt 2 x = 1\frac{1}{4}\pi + k \cdot 2\pi of x = 1\frac{3}{4}\pi + k \cdot 2\pi of x = \frac{1}{4}\pi + k \cdot 2\pi of x = \frac{3}{4}\pi + k \cdot 2\pi x = \frac{1}{4}\pi + k \cdot \frac{1}{2}\pi
