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Re: How to solve this type of equation in Mathematica?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg59976] Re: How to solve this type of equation in Mathematica?
  • From: robert.dodier at gmail.com
  • Date: Sat, 27 Aug 2005 04:11:05 -0400 (EDT)
  • References: <dehk3h$c9t$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

> That is I would like to solve for f(x) when we know that
> integrating  (x + P) f(x) from P to Infinity over x equals 1.

It looks to me like this isn't strong enough
to yield a unique solution (or even a solution in
a well-known class).

If you replace f by A f where A is a constant
you get A times \int_P^{\infty} (x + P) f(x) dx.
So let f be any function s.t. the integral is defined
and not equal to zero. (I believe that's a fairly
large class.) If the integral I is not equal to 1,
replace f by f/I and that's a solution,
if I'm not mistaken.

The equation is an example of an integral equation,
so you might be able to find more info under that
heading. Sorry that I can't be more helpful.

Robert Dodier


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