Ва
Василий
Нет, не так.
2* sin(x) + cos(4x) = 0
2*sin(x) - 1 + 2cos(2x) = 0
-cos(2x) +2cos(2x) = 0
cos(2x) = 0
cos(2x) = 1/2
x = -π/4 + π*k /2
x = π/6 + π*k
x = -π/6 + π*k
k - целое