2sin (7π/2+x) * sin x = √3 cos x, [-7π; -6π]

2sin (7π/2 + x) * sinx = √3*cosx

2sin (π/2 + x) sinx = √3cosx

2cosxsinx - √3cosx = 0

cosx (2sinx - √3) = 0

1) cosx = 0

x₁ = π/2 + πk, k∈Z

2) 2sinx - √3 = 0

sinx = √3/2

x = (-1) ^ (n) * arcsin (√3/2) + 2πn, n∈Z

x₂ = (-1) ^ (n) * (π/3) + 2πn, n∈Z