sin(x+y)=0 x+y=Пk
sin(x-y)=-1 x-y=2Пk-П/2
2x=3Пk-П/2
x=3Пk/2-П/4=П/4(6k-1)
2y=П/2-Пk=П/2(1-2k)
y=П/4(1-2k)