# If Cos(t)=-7/8 with #pi<=t<=3pi/2#, how do you find the value of sin(2t)?

##### 1 Answer

Apr 7, 2016

#### Explanation:

sin 2t = 2sin t.cos t

Knowing

Trig identity:

sin t = +- sqrt15/8.

Arc t is in Quadrant III, then, sin t is negative.