# Improper Integrals

1. Apr 12, 2009

### Mathematics07

[\The question is to evaluate the integral from 1 to infinity of ∫[(1)/(3x+1)^2] dx.

No idea how to do this can anyone help explain improper integrals please.

THE ANSWER TO THE PROBLEM IS 1/12 thought . . . .

Thanks

2. Apr 12, 2009

### Feldoh

You need to find the anti-derivative and then evaluate it the anti derivative like normal, just take the limit as the upper limit of integration goes to infinity.

3. Apr 12, 2009

### dextercioby

To find that antiderivative, just substitute ' 3x +1 = p ' and then express the whole deal in terms of ' p ' .