# Given #tantheta=-3/4# and #90<theta<180#, how do you find #tan(theta/2)#?

##### 1 Answer

Sep 26, 2016

#### Explanation:

Call tan (t/2) = x and use trig identity:

Cross multiply:

Solve the quadratic equation for x.

There are 2 real roots:

x1 = 3, and

and

Because t is in Quadrant II, then

There for: