# Exponential Integral - Integration by Parts with Inverse Functions

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• Jul 21st 2009, 04:07 AM
m.walunga
Exponential Integral - Integration by Parts with Inverse Functions
Can someone walk through this and let me know if everything is all right? I have a bad habit of making mistakes with my math and getting excited over nothing (Headbang).

You can find my work here: http://img9.imageshack.us/img9/4702/...279204d696.png
http://img9.imageshack.us/img9/4702/...279204d696.png

Please post back whatever you find. I'd like to know if you feel it's valid, if it's invalid, why it's invalid, and I'd be glad to explain how I got any particular part.
...yeah I know, reusing variables is a nasty habit but you get the idea =-P.(Nerd)
• Jul 21st 2009, 06:55 AM
Krizalid
When integrating by parts $e^x\ln x,$ the RHS is wrong, it should be $e^{x}\ln x-\int{\frac{e^{x}}{x}\,dx}.$

And well... no elementary primitive for this thing.

(Please reduce the size of your image.)
• Jul 21st 2009, 07:19 AM
m.walunga
You even caught it with the e^x*dx that weren't supposed to be there ><. How did I not catch that?

Thank you!