0\\4-x^2>0\\(x-2)(x+2)>0\\x\in(-4;4)\\\\cosx<0\\x\in( \frac{\pi}{2}+2\pi n; \frac{3\pi}{2}+2\pi n), n\in Z " alt="cosx \sqrt{4-x^2}<0\\\\ \sqrt{4-x^2}>0\\4-x^2>0\\(x-2)(x+2)>0\\x\in(-4;4)\\\\cosx<0\\x\in( \frac{\pi}{2}+2\pi n; \frac{3\pi}{2}+2\pi n), n\in Z " align="absmiddle" class="latex-formula">