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xnr
Oct19-09, 07:07 AM
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 and

(sorry I could not get the integral symbol to work, so I used int instead)

thanks
xnr

HallsofIvy
Oct19-09, 07:22 AM
Neither of those looks convergent (at 0) to me.

g_edgar
Oct19-09, 09:52 AM
As Halls said, they diverge at 0. The indefinite integral of exp(y)/y is a non-elementary function known as the "exponential integral" function. Your two integrals may be expressed in terms of the exponential integral function using integration by parts.