Answer:
<em>Answer:</em> <em>A</em> 
Step-by-step explanation:
The HL Theorem states that if the hypotenuse and leg of one right triangle are congruent to the hypotenuse and leg of another right triangle, then the two triangles are congruent.
Triangles TRO and OMT share the hypotenuse, so the first part of the theorem is met.
Both triangles are right because they have an internal angle of 90°, so the second condition is also met.
Since there is no indication of any leg to be congruent to another leg, we need additional information to prove that both triangles are congruent.
One of these two conditions should be met:
Side TM is congruent to side OR, or
Side MO is congruent to side RT.
From the available options, only the first is correct.
Answer: A 
The double angle formula for the sine is

The right hand side is exactly your expression, where 
So, rewriting the expression from right to left, we have

Answer:
What is the question?
Step-by-step explanation:
1. Write all of the question to receive a correct answer.
Answer:
15
Step-by-step explanation: