Question

Решите уравнение Sin 4xCos 2x=2 Sin x

Answer 1

sin4x/cos2x = 2sinx
2sin2x*cos2x / cos2x = 2sinx
2sin2x - 2 sinx = 0
2sinxcosx - sinx = 0
sinx(2cosx - 1) = 0
1)  sinx = 0
x1 = πn, n∈Z
2)  2cosx - 1 = 0
cosx = 1/2
x = (+ -)arccos(1/2) + 2πk, k∈Z
x2 = (+ -)*(π/3) + 2πk, k∈Z