sinxcosx*cosx/sinx-cosx=sin^2x
cos^2x-cosx-sin^2x=0
2cos^2x-cosx-1=0
cosx=t
2t^2-t-1=0
(1+-3)/4
t1=1
t2=-1/2
cosx=1 x=2Пk x1=0
cosx=-1/2
x=+-2П/3+2Пk x2=2П/3
sinxcosx*cosx/sinx-cosx=sin^2x
cos^2x-cosx-sin^2x=0
2cos^2x-cosx-1=0
cosx=t
2t^2-t-1=0
(1+-3)/4
t1=1
t2=-1/2
cosx=1 x=2Пk x1=0
cosx=-1/2
x=+-2П/3+2Пk x2=2П/3