It is already in identity.
cos (x - y) - cos (x + y) = 2 sin(x) sin (y)
Here is you're answer:
In order to get you're answer you need to find the common denominator then add.

- Find the common denominator:


- Simplify:
-


Therefore you're answer is option D "13/24."
Hope this helps!
Answer:
In the picture
Step-by-step explanation:
I hope that it's a clear explanation.
The answer would be 15.7142857143
You can get the answer by calculating (5/7) × 22
Answer:
73
Step-by-step explanation: