There various ways to go about it.
Make the sub
This whittles it down to:
Now, can you finish it up?.
I would use an algebraic simplification first. Build the fraction using (1+x) to get
The first is the arcsine and the 2nd is a u sub. I hope this helps.
Note: I didn't use absolute values in the 3rd equality because the domain is so the numerator is always posative there.