Question #fe8b2
2 Answers
Explanation:
Use trig identity:
sin 2x = 2sin x.cos x.
First, find cos x by the trig identity:
In this case:
There are 2 values of cos x because
Next find sin x.
Finally:
Remark.
If x is in Q. 1 --> 2x is in Q. 2 --> sin 2x is positive.
If x is in Q. 3 --> 2x is in Q. 1 or Q. 22 --> sin 2x is also positive
Given:
Because the tangent is negative, we know that
We know that
We can start with the identity
We deduced that
Substitute the given value for the tangent function;
Use the identity,