sinx/2 + cosx/4 + sinx = 0

sin (x/2) + cos (x/4) + sinx=0;

2sin (3x/4) * cos (x/4) + cos (x/4) = 0;

cos (x/4) * (2sin (3x/4) + 1) = 0;

cos (x/4) = 0;

x/4=π/2+πn. n∈Z.

x=2π+4πn. n∈Z.

2sin (3x/4) + 1=0;

sin (3x/4) = - 1/2;

3x/4 = (-1) ^ (n+1) * (π/6) + πk. k∈Z.

x = (-1) ^ (n+1) * (2π/9) + πk. k∈Z.

Легкое уравнение ...