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prasat July 4, 2003 07:34

A simple question on integration.
 
Hi I just want to integrate analytically.

sqrt[(1/x)(exp(-x)-1)]

thanks in advance prasat

mehdi July 4, 2003 08:54

Re: A simple question on integration.
 
Hi, It isn't so easy for directly integration but you can write tylor series for exp(-x), I think in this way it will be simpler.

prasat July 4, 2003 09:07

Re: A simple question on integration.
 
Yes I already did that it works very well from exp(-x)=1 nad exp(-x)=1-x after that when I substitute exp(-x)=1-x+0.5*x^2 I have diffculty in integrations. SQRT(3x-x^2) prasat

mehdi July 4, 2003 11:58

Re: A simple question on integration.
 
You can find it from mathematics handbook:you can chech this:

I= -x^.5/2*(3-x)^(3/2)+4/3*(3-x)^.5+2*(1/3^.5)*(ln(u)

U=(((3-x)^.5-3^.5)/((3-x)^.5+3^.5)))

Jonas Holdeman July 4, 2003 21:19

Re: A simple question on integration.
 
Anyone with difficult integrals to evaluate (and that includes most of us at one time or another) should be aware of the classic text, "Tables of Integrals, Series and Products" by I. S. Gratshteyn and I. M. Rhyzhik. Originally translated from Russian, it is in its sixth edition (Aug 2002) and costs $79.95 from Elsevier. It was originally dirt cheap but is still a bargain. There is an older fifth edition from Academic Press for $99.95. (These prices from Barnes & Noble).


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