# Integral help

1. Feb 4, 2008

### jhayes25

1. The problem statement, all variables and given/known data
Not real good with the easy text stuff yet so ill give it a shot.

definite integral of (1/(1+t^2))dt from 0 to x^2
then find the interval for which the curve is concave upward.

I totally forgot how to integrate problems like this. It is some sort of substitution I know.

Help?

Would the integral of this involve a natural log?

Last edited: Feb 4, 2008
2. Feb 4, 2008

### PowerIso

What you have in your integral is arctan. Probably something you should memorize.

3. Feb 4, 2008

### Kurdt

Staff Emeritus
You'd need a trigonometric substitution for that integral. It works out quite neatly in the end.

Or recognise that the integrand is the derivative of arctan.

Last edited: Feb 4, 2008
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