Question

Срочно нужно заранее спасибо
2) 4cos x * cos 2x * cos 3x - cos 6x = 0 ;
3) sinx * sin2x * sin3x - 1/4 * sin4x =0
4) cosx * cos2x * cos4x * cos8x - 1/8* cos15x=0

Answer 1

Ответ:

2) 4cos x * cos 2x * cos 3x - cos 6x = 0

=> 4cos x (1 - 2sin ^2 x) (1 - 3sin ^2 x) - 1/2 * sin6x = 0

=> 4cos x (1-5sin^2 x+4sin^4 x - 3sin ^6 x) =0

=> 4cos x (1 - 5sin^2 x)(1-sin^2 x) = 0

=> 4cos x (1 - 4sin

3) sinx * sin2x * sin3x - 1/4 * sin4x =0

=> sinx (sin2x sin3x -1/2 sin4x) = 0

=> sinx (3sin ^3 x - 1/2 * 2sin^3 x sinx) = 0

=> sinx (3sin^3 x - sinx) = 0

4) cosx * cos2x * cos4x * cos8x - 1/8* cos15x=0

=> cosx (cos2x cos4x - 1/4 cos15x) = 0

=> cosx (cos2x - 1/2 cos2x cos11x) = 0

=> cosx (cos2x(1 - cos11 x)) = 0

=> cosx (cos2x * (1 - cos11x)) = 0