Answer: D
Explanation:
The answer is D, and here's why:
So, other than the basic three trigonometric functions (sin, cos, tan), there's also (sec, csc, cot). These values are based on the basic three, but are flipped around. So, sec is equivalent to 1/sin.
Keeping that in mind, cot (cotangent) is tangent flipped around, so it's cos/sin.
Using the identity on the left side, we can expand it out to cos * cos over sin, where one cos is separated while the other is divided by sin to give an answer of cotangent.
Since sin is in the denominator, it will stay as the denominator.