# Unsure where to start

1. Jul 27, 2011

### FecalFrown

1. The problem statement, all variables and given/known data
Howdy fellas, long time lurker, first time poster. If someone could get me started on the right track for this problem, it would be appreciated.

Also, I'm not sure how to write equations yet, but I'll do my best to explain the problem clearly

2. Relevant equations

Int[1 to 2] Int[0 to x] of 1/(sqrt((x^2)+(y^2)))dydx

3. The attempt at a solution

As I said, not sure how to get started. My gut was telling me to raise the denominator to the -1/2 power and use the substitution rule? But I'm not sure.

Thanks

2. Jul 27, 2011

### micromass

Staff Emeritus
Hi FecalFrown!

Let's start with the inner integral, this is

$$\int_0^x{\frac{1}{\sqrt{x^2+y^2}}dy}$$

where x is simply a constant. The trick is to factor x out of the square root, and then to do a trigonometric substitution $\frac{y}{x}=\tan(\theta)$

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook