Cos3xcos2x-sin3xsin2x=-√2/2помогите)))))

Question

Cos3xcos2x-sin3xsin2x=-√2/2помогите)))))

Answer 1

Сos 3x* cos 2x - sin 3x* sin 2x = - sgrt2/2;
cos(3x+2x) = - sgrt2/2;
cos 5x = - sgrt2/2;
5x = + - (3pi/4) + 2*pi*k;
x = + - (3pi/20) + 2pi*k/5; k-Z