which is the integral for exp( -a/x ) dx ?

i have tried every method

thanks

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- Sep 7th 2006, 02:04 PMv71nasty integral
which is the integral for exp( -a/x ) dx ?

i have tried every method

thanks - Sep 7th 2006, 03:11 PMtopsquarkQuote:

Originally Posted by**v71**

-Dan - Sep 7th 2006, 04:34 PMThePerfectHacker
Topsquark is correct.

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It is a famous case that,

is non-elementary.

We shall convert this integral into this form.

For simplicity sake we shall use , thus,

Manipulate it as,

Let, (going to apply the substitution rule)

then,

Thus,

If you use integration by parts with,

and

Then,

We have converted this integral into an integral which has no elementary anti-derivative. This confirms topsquarks guess. - Sep 7th 2006, 04:44 PMtopsquarkQuote:

Originally Posted by**ThePerfectHacker**

-Dan