Question

Помогите решить пж cox2x+sinx=0

Answer 1

$\cos(2x) + \sin(x) = 0 \\ 1 - 2 \sin(x)^{2} + \sin(x) = 0 \\ 1 - 2t ^{2} + t = 0 \\ \\ t = 1 \\ t = - \frac{1}{2} \\ \\ \sin(x) = 1 \\ \sin(x) = - \frac{1}{2} \\ \\ x = \frac{\pi}{2} + 2k\pi \\ x = \frac{11\pi}{6} + 2k\pi \\ x = \frac{7\pi}{6} + 2k\pi \\ \\ OTBET: x = \frac{\pi}{2} + \frac{2k\pi}{3}$