Мега сложно, спасайте (((

Решите задачу:

$1)\quad y=4cost-4\\\\-1 \leq cost \leq 1\\\\-4 \leq 4cost \leq 4\\\\-8 \leq 4cost-4 \leq 0\\\\y(naibol.)=0\\\\2)\quad sin(\frac{4\pi}{3})+sin(-\pi )+sin(-\frac{\pi}{6})+sin(-\frac{\pi}{2})=\\\\=sin(\pi +\frac{\pi}{3})-sin\pi -sin\frac{\pi}{6}-sin\frac{\pi}{2}=\\\\=-sin\frac{\pi}{3}-0-\frac{1}{2}-1=-\frac {\sqrt3}{2}-\frac{3}{2}\; ;\\\\Otvet :\; \; \#1\; .$