Answer:
B) 24/25
Explanation:
You're asked to find the exact value of the composition ...
sin(2·arccos(3/5))
You know the double angle formula for the sine is ...
sin(2x) = 2sin(x)cos(x)
and you know the sine can be derived from the cosine by ...
sin(x) = √(1 -cos(x)^2)
Since you're given the cosine as 3/5, this means you need to find the value of ...
sin(2·arccos(3/5)) = 2·√(1 -(3/5)^2)·(3/5) = 2·(√(25-9))/5·3/5 = 2·4/5·3/5
sin(2·arccos(3/5)) = 24/25 . . . . . . matches the marked answer
_____
If you do this on your calculator, you will find the result to be 0.96, which is the decimal value of 24/25.