This is LaTeX code:
[latex]
= \left( {\frac{{y_0 - iy_1 }} {2} + \frac{{y_0 + iy_1 }} {2}} \right)\cos x + \left( {\frac{{y_0 - iy_1 }} {2} - \frac{{y_0 + iy_1 }} {2}} \right)i\sin x =
[/latex]