Evaluate the $\sin$, $\cos$ and $\tan$ without using calculator? 
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 right answer are $\frac{1}{\sqrt{2}}$, $\frac{1}{\sqrt{2}}$ and $1$.

Two more possibilities:


*

*Use a table of trigonometric values.

*Use a ruler and a protractor in drawing the line values of the trigonometric functions.  (See, for example, this.)

