Быстрый ответ
x1 = 0 x2 = pi/2 x3 = 3*pi/2
x1 = 0 pi x2 = -- 2 3*pi x3 = ---- 2
$$x_{1} = 0$$<br><br>$$x_{2} = \frac{\pi}{2}$$<br><br>$$x_{3} = \frac{3 \pi}{2}$$