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:
60 ways;
GOOD LUCK!
Step-by-step explanation:
The word CHEWY has 5 letters, Therefore, it can be arranged in 5!/2! = 120/2 = 60 ways.
Answer:
The standard number is greater than one. Negative means it's going to be .xxx