# Given #tanA=-3/4, 0<A<pi#, what is #sin(2A)#?

##### 1 Answer

Mar 6, 2017

#### Answer:

#### Explanation:

Use trig identity:

In this case:

Because 0 < A < pi, therefore, sin A is positive.

Because tan A is negative, therefore, A is in Q. 2, cos A is negative.