2Sin^2 x +(2 - √2)cosx + √2 - 2 = 0

[latex]2(1-cos^{2}x)+(2-\sqrt{2})(cosx-1)=0 \\ -2(cos^{2}x-1)(cosx+1)+(2-\sqrt{2})(cosx-1)=0 \\ (cosx-1)(-2cosx-2+2-\sqrt{2})=0 \\ cosx=1 \ \ \ x=2\pi n \\ -2cosx=\sqrt{2} \ \ \ cosx=-\frac{\sqrt{2}}{2} \\ x=+-\frac{3 \pi}{4} +2\pi k [/latex] Где k принадлежит целым числам.