# Homework Help: Calc II: Help Solving this Integral

1. Jun 18, 2012

### Hertz

1. The problem statement, all variables and given/known data

$\int \frac{\sqrt{9 - x^2}}{x} dx$

2. The attempt at a solution

x = 3sin(u)
dx = 3cos(u)du
u = arcsin(x/3)

$\int \frac{3\sqrt{cos(u)^2}}{3sin(u)} 3cos(u)du$

$3 \int \frac{cos(u)}{sin(u)} cos(u)du$

Don't really see anywhere to go from here. Apologies if the work is hard to follow, I cut out a few steps because inputting equations is a real pain in my opinion.

2. Jun 18, 2012

### Staff: Mentor

Write cos2(u) as 1 - sin2(u), and then split into two integrals.

3. Jun 18, 2012

### Hertz

Ah! Thank you, I'll give it a try