Add positive 28 to get the sum 0
1. 5/6
2. 3/4
3. 2/3
4. 1/6
5. 1/4
6. 1/2
Answer: Option d.
Step-by-step explanation:
The trigonometric identity needed is:

Knowing that
:
Substitute it into
:

Simplify the expression:

Solve for
. Apply square root at both sides of the expression:

