# Math Help - help with an integral involving the exp function

1. ## help with an integral involving the exp function

Hi everyone

I've been dealing with a rather difficult (at least for me) integration problem which I am not able to find in integration tables I've been consulting.
After a variable transformation I ended up with the following sets of integrals:

$\int e^{y}/y^{2}dy$ from 0 to t (t is not infinity) and

$\int e^{y}/y^{3}dy$ also from 0 to t

I ended up with these starting from

$\int A*e^{B/(C-D*x)}*xdx$ (A,B,C and D are constants) from 0 to infinity and using the transform

$y=B/(C-D*x)$

any ideas?

thanks
xnr

2. You should be able to use integration by parts to get the indefinite integrals - eg for the first, apply once to get the integral e^y/y, then integrating this by parts gives you an integral of e^y * ln y. Apply parts once more and you should be able to get the result