Question

$sin x \geq -\sqrt{2}/2$
$sin x \geq 1$
$cos x \leq -1$

Answer 1

Ответ.

$1)\ \ sinx\geq -\dfrac{\sqrt2}{2}\\\\-\dfrac{\pi }{4}+2\pi n\leq x\leq \dfrac{\pi}{4}+2\pi n\ ,\ n\in Z\\\\2)\ \ sinx\geq 1\\\\x=\dfrac{\pi}{2}+2\pi n\ ,\ n\in Z\\\\3)\ \ cosx\leq -1\\\\x=\pi +2\pi n=\pi (2n+1)\ ,\ n\in Z$