Use the formula

to find the values of:

1. $$\tan \left(\frac{\pi }{12}\right)$$
2. $$\tan \left(\frac{5\pi }{12}\right)$$
3. $$\tan \left({165}^{\circ }\right)$$

For (a),

For (b),

or you could do

and make use of the answer to part (a).

For (c), notice that

In part (a), we found $\tan \left(\frac{\pi }{12}\right),$ and $\frac{\pi }{12}$ rad is ${15}^{\circ }.$