2 sin^2 x(sin x +1) = (2cos^2 x - 1) * sin x +(2 cos^2 x -1);
2 sin^2 x(sin x + 1) =(2 cos^ x - 1) *(sin x + 1);
(sin x + 1) (2 sin^2 x - (2 cos^2 x - 1))=0;
(sin x +1 ) (2 sin^2 x - 2 cos^2 x +1)=0; /*(-1);
-(sin x +1) *(2 cos^2 x - 2 sin^2 x -1)=0;
(sin x + 1) (cos (2x) - 1) =0;
1) sin x + 1 = 0 ;⇒ sin x = -1; x = - pi/2 + 2pi*k; k-Z.
2) cos(2x) - 1=0;⇒ cos 2x = 1; 2x =2 pi*k; x = pi*k; k-Z.
Ответ: х = pik;
x= - pi/2 + 2 pik; k-Z