geometry - Evaluate the $\sin$, $\cos$ and $\tan$ without using calculator? - Mathematic
Evaluate the $\sin$, $\cos$ and $\tan$ without using calculator? $150$ degree the right answer are $\frac{1}{2}$, $-\frac{\sqrt{3}}{2}$and $-\frac{1}{\sqrt{3}} $ $-315$ degree the ... ... It is very simple. $\sin(150) =...