1) sinxsiny=1/a cosxcosy=1/b 2) cosx+cosy=дробь3/c x+y=p/3 решите уравнение

sinxsiny=1/a cosxcosy = 1/b

сos (x-y) - cos (x+y) = 2/a

сos (x-y) + cos (x+y) = 2/b

2 сos (x-y) = 2/a+2/b cos (x-y) = (a+b) / ab x-y = + - arccos[ (a+b) / ab]+2πk

2cos (x+y) = 2/b-2/a cos (x+y) = (a-b) / ab x+y = + - arccos[ (a-b) / ab]+2πm

x=+-0.5arccos[ (a+b) / ab]+-0.5arccos[ (a-b) / ab]+π (k+m)

y=+-0.5arccos[ (a-b) / ab]+-0.5arccos[ (a+b) / ab]+π (m-k) m, k∈Z