Re: Finding the inverse of a function?

*To*: mathgroup at smc.vnet.net*Subject*: [mg24198] Re: Finding the inverse of a function?*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Fri, 30 Jun 2000 01:57:27 -0400 (EDT)*Organization*: Universitaet Leipzig*References*: <8jebnp$jen@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Hi, which one ? if you have Sum[a[i]x^i,{i,0,n}]=y Mathematica can try to Solve[] the polynom equation but you will get n solutions and Mathematica can't decide for you what solution is your inverse function. Since only for n<=4 exact formulas are known Mathematica may not be able to find all solutions as readable (not Root[] objects) expressions. Regards Jens heathw at in-tch.com wrote: > > Hi, > Is there some way to make Mathematica find the inverse of a user defined > function? I read the Mathematica Book and found InverseFunction[ ] but > it will only show the inverse of a Mathematica function. I would like to > be able to find the inverse of polynomials. > Thanks, > Heath