1. C
2. A
3. B
Hope This Helped!
<u><em>(Brainliest will be appreciated)</em></u>
The quickest way to get the series is if you already know the series for sine:

Then just multiply the series by
to get

The first four nonzero terms are simply the first four terms:

Answer:
Since the sum is 38, y must be 15. And indeed the difference between 23 and 15 is 8, so it's correct.