- 25

- 0

**1. Homework Statement**

Evaluate the Integral: Sqrt[(X^2)+9]

**2. Homework Equations**

I know its an Integration By parts problem, but I dont know how to start it.

**3. The Attempt at a Solution**

Im JUST learning this as I type this problem out, Ive just been stuck on it for a while and my book does a horrible job of explaining how to do problems. If anybody could explain the Trigonometric substitution technique or knows of a good website that explains it I would be very grateful.

For this problem though, all I did was set x=3sin(u) and dx=3cos(u).

I dunno if thats right though, because like I said, I just "learned" this yesterday