Помогите. Тригонометрия

[latex]1)\quad sinx \leq 0\\\\-\pi +2\pi n \leq x \leq 2\pi n\; ,\; n\in Z\\\\2)\quad cos^2x\ \textgreater \ \frac{1}{2}\\\\\frac{1+cos2x}{2}\ \textgreater \ \frac{1}{2}\\\\\frac{cos2x}{2}\ \textgreater \ 0\\\\cos2x\ \textgreater \ 0\\\\-\frac{\pi}{2}+2\pi n\leq 2x \leq \frac{\pi}{2}+2\pi n\; ,\; n\in Z\\\\-\frac{\pi}{4}+\pi n\leq x\leq \frac{\pi}{4}+\pi n\; ,\; n\in Z[/latex]