# Integrate substraction of squareroots

1. Nov 19, 2012

### Blastrix91

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

I'm having some troubles with my calculus. I can't get from the first step to the second step in the example below:

2. Relevant equations

http://img853.imageshack.us/img853/4350/unavngivetpn.png [Broken]

3. The attempt at a solution

$$\int_{-L/2}^{L/2} [R^2 + (Z-Z_0)^2]^{1/2} - \int_{-L/2}^{L/2} [(Z-Z_0)^2]^{1/2}$$

The last term I have calculated to be $-Z_0 L$ which matches the solution. The first term however I'm having some problems with. Is trig substitution necessary here?

Last edited by a moderator: May 6, 2017
2. Nov 19, 2012

### I like Serena

3. Nov 19, 2012

### Dick

And, yes, to derive the result in the table you want a trig or hyperbolic trig substitution.