-√2 sin(-5π/2+x)*sinx=cosx
√2 sin(5π/2-x)*sinx=cosx
√2 sin(π/2-x)*sinx=cosx
√2 cosx*sinx=cosx
cosx(√2sinx-1)=0
x=π/2+π*n
x=π/4+2π*m
x=3π/4+2π*m
x=4,5π;5,5π;6,5π;7,5π;8,5π;π/4+6π, π/4+8π, 3π/4+6π, 3π/4+8π
