Trigonometric Identities

Given:

We need to find the value of .

First, recall that . Substitute in the given equation:

Let . Then we have:

Multiply through by to eliminate the fraction:

Rearrange to form a quadratic equation:

Observe that this is a perfect square:

Thus, , which means .

Now, find :

, so

Therefore, .

The value of is 2.

Given that and is in the first quadrant, we need to find . In the first quadrant, both sine and cosine values are positive. We know the identity .

Substitute into the identity:

Solve for :

Take the positive square root (since is in the first quadrant):

Thus, the correct answer is .