Answer:
D
Step-by-step explanation:
We are given that:
And we want to find the value of tan(2<em>x</em>).
Note that since <em>x</em> is between π/2 and π, it is in QII.
In QII, cosine and tangent are negative and only sine is positive.
We can rewrite our expression as:
Using double angle identities:
Since cosine relates the ratio of the adjacent side to the hypotenuse and we are given that cos(<em>x</em>) = -1/3, this means that our adjacent side is one and our hypotenuse is three (we can ignore the negative). Using this information, find the opposite side:
So, our adjacent side is 1, our opposite side is 2√2, and our hypotenuse is 3.
From the above information, substitute in appropriate values. And since <em>x</em> is in QII, cosine and tangent will be negative while sine will be positive. Hence:
<h2>Simplify:
Evaluate:
The final answer is positive, so we can eliminate A and B.
We can simplify D to:
So, our answer is D.