2sin7x*cos2x+Sin4x=0 решите

2sin (7x) * cos (2x) + sin (4x) = 0

2sin (7x) * cos (2x) + 2sin (2x) * cos (2x) = 0

2Cos (2x) * [sin (7x) + sin (2x) ]=0

1. cos (2x) = 0

2x=pi/2+pi*n

x=pi/4+pi*n/2

2. sin (7x) + sin (2x) = 0

2sin ((7x+2x) / 2) * cos ((7x-2x) / 2) = 0

2sin (9x/2) * cos (5x/2) = 0

sin (9x/2) * cos (5x/2) = 0

a) sin (9x/2) = 0

9x/2=pi*n

9x=2pi*n

x=2pi*n/9

б) cos (5x/2) = 0

5x/2=pi/2+pi*n

5x=2pi/2+pi*n

x=2pi/10+pi*n/5