# If Cos 12/13, Sin<0, how do you find tan in simplest form?

May 18, 2016

$- \frac{5}{12}$

#### Explanation:

If cos a = 12/13. angle is in either 1st quadrant or in the 4th.

$\sin a = \pm \frac{5}{13}$ As sin a < 0, a is in the 4th quadrant. So, $\sin a = - \frac{5}{13}$.

Thus, the ratio sin a/ cos a = tan a = -5/12..