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Re: Unsolved integral

  • To: mathgroup at smc.vnet.net
  • Subject: [mg8861] Re: [mg8826] Unsolved integral
  • From: David Withoff <withoff>
  • Date: Tue, 30 Sep 1997 20:16:22 -0400
  • Sender: owner-wri-mathgroup at wolfram.com

> Dear colleagues,
> I'm trying to solve the following integral :
> Integrate[(1-a-x)^(0.5) (1/x)^(0.5)   1/((1-a-x)^2-4*a*b*x)^(0.5)),{x,0,1-a}]
> but Mathematica 3.0 gives it back to me. I would be very appreciate if 
> somebody tells me how to solve it. 
> Best regards:
> Jose M. Ramon <jose.m.ramon at uv.es>

Try replacing the inexact exponents (0.5) with exact exponents (1/2).
There is a syntax error in this input (and maybe a plus-sign that
got dropped in the transmission?) so I wasn't able to try this example,
but with the inexact exponents the integral is probably impossible.
Try it with exact exponents.

Similar concerns with inexact exponents apply to most algebraic operations.
For example c0 + c1 x + c2 x^2 == 0 is a simple quadratic equation,
while c0 + c1 x + c2 x^(2.0) == 0 is an awkward, underspecified problem.

Dave Withoff
Wolfram Research


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