Question

Решите уравнение: Cos(x - П/2) = -1

Answer 1

$\cos(x - \frac{\pi}{2} ) = - 1 \\ \sin(x) = - 1 \\ x = \frac{3\pi}{2} + 2k\pi$

Answer 2

$\cos(x - \frac{\pi}{2} ) = - 1 \\ \cos( - \frac{\pi}{2} + x ) = - 1 \\ \cos( - ( \frac{\pi}{2} - x ) = - 1 \\ \cos( \frac{\pi}{2} - x ) = - 1 \\ \sin(x ) = - 1 \\ x = \frac{3\pi}{2} + 2k\pi$