ANSWER
True
EXPLANATION
The given trigonometric equation is:

We take the LHS and simplify to arrive at the RHS.

Collect LCM on the right hand side to get;

This implies that



This identity has been verified .Therefore the correct answer is true.
Answer:
55
Step-by-step explanation:
The 6 terms of the series are
... 15, 14, 13, 12, 11, 10
The sum of them is 75.
_____
You could make use of the formula for the sum of the terms, or you could work out the sum from the given expression. It is easier just to list the terms and and them up.