<u>Sin x</u> +Sin 2x <u>- Sin 3x</u> =0 2Sin(-x) Cos 2x +sin 2x = 0 -2Sin x Cos 2x +Sin 2x = -2Sin x(1 - 2Sin^2 x) + 2Sin x Cos x= 0 -2Sin x +2Sin^3 x + 2Sin xCos x = 0- -2Sin x (1 + Sin^2 x -Cos x) = 0 Sin x = 0 x = πn,где n∈Z или 1 + Sin^2 x - Cos x=0 1 + 1 - Cos^2 x - Cos x = 0 Cos^2 x + Cos x - 2 = 0 Cos x = -2 (нет решений) Сos x = 1 x = 2πk,где к∈Z