√2sin²(π/2+х)= sin( 3π/2+x)

[latex] \sqrt{2} cos ^{2 } x=cosx cosx(\sqrt{2} cosx-1)=0 cosx=0, cosx=1/ \sqrt{2} x= \pi /2+ \pi n. x= \pi /4+2 \pi n x=- \pi /4+2 \pi n [/latex]