Решите систему уравнений: x-y=π/3; cosXcosY=1/2 спасибо!!!

Решите задачу:

$\left \{ {{x-y= \frac{\pi }{3}} \atop {cosx\, cosy=\frac{1}{2}}} \right. \; \left \{ {{x=y+ \frac{\pi }{3} } \atop {\frac{1}{2}(cos(x-y)\, cos(x+y))= \frac{1}{2}}} \right. \; \left \{ {{x=y+\frac{\pi}{3}} \atop {cos\frac{\pi}{3}+cos(2y+ \frac{\pi}{3} )=1}} \right. \\\\ \left \{ {{x=y+\frac{\pi}{3}} \atop {cos(2y+\frac{\pi}{3})=\frac{1}{2}} \right. \; \left \{ {{x=y+\frac{\pi}{3}} \atop {2y+\frac{\pi}{3}=\pm \frac{\pi}{3}+2\pi n,\; n\in Z}} \right. \; \left \{ {{x=y+\frac{\pi}{3}} \atop {2y=-\frac{\pi}{3}\pm \frac{\pi}{3}+2\pi n,\; n\in Z}} \right.$

$\left \{ {{x=y+ \frac{\pi}{3}} \atop {2y=2\pi n,\; n\in Z}} \right. \; \; ili\; \; \left \{ {{x=y+\frac{\pi}{3}} \atop {2y=-\frac{2\pi}{3}+2\pi n,\; n\in Z}} \right. \\\\ \left \{ {{x=\frac{\pi}{3}+\pi n,\; n\in Z} \atop {y=\pi n,\; n\in Z}} \right. \; \; ili\; \; \left \{ {{x=\pi n,\; n\in Z} \atop {y=-\frac{\pi}{3}+\pi n,\; n\in Z}} \right. \\\\Otvet:\; \; (\frac{\pi }{3}+\pi n\; ;\; \pi n)\; ,\; \; (\pi n\; ;\; -\frac{\pi }{3}+\pi n) \; .$