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

*To*: mathgroup at smc.vnet.net*Subject*: [mg60072] Re: How to solve this type of equation in Mathematica?*From*: spousta at yahoo.com*Date*: Thu, 1 Sep 2005 02:13:08 -0400 (EDT)*References*: <dehk97$cbs$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Hi try to suppose f(x) in the form a /(x^3) for an unknown parameter a Equal[Integrate[Times[Plus[P, x], Times[a, 1/(x x x)]], List[x, P, DirectedInfinity[1]]], 1] Then you get a = 2 P / 3 The same game can be played with another integrable functions - I suspect you will have too much possible solutions :-) Greetings Jan Jeffrey Lyons wrote: > Hi, I would like to be able to solve the equation: > > Equal[Integrate[Times[Plus[P, x], f[x]], List[x, P, > DirectedInfinity[1]]], 1] > > in Mathematica. Is there any way to do this? > > 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.