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Simple question about inverse of a function

• To: mathgroup at smc.vnet.net
• Subject: [mg122502] Simple question about inverse of a function
• From: Mikael <mikaen.anderson.1969 at gmail.com>
• Date: Sun, 30 Oct 2011 04:22:58 -0500 (EST)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com

I have a simple question on how to calculate the inverse of a a function. This is the function I define:

f[t_] := (1 - t)^theta

To calculate the inverse I write:

Assuming[t >= 0 && t <= 1 && theta >= 1 && theta < Infinity, { InverseFunction[f[t]]}]

but the answer I get is

{InverseFunction[(1 - t)^theta]}.

Now I know I can do this:

In[11]:= Solve[f[g[x]]==x,g[x]]
Out[11]= {{g[x]->1-x^(1/theta)}}

but I wonder what is the correct way of specifying assumptions on t and theta to make the InverseFunction work. Thanks.

• Follow-Ups:
  • Re: Simple question about inverse of a function
    • From: Andrzej Kozlowski <akoz@mimuw.edu.pl>
  • Re: Simple question about inverse of a function
    • From: DrMajorBob <btreat1@austin.rr.com>
  • Re: Simple question about inverse of a function
    • From: Bob Hanlon <hanlonr357@gmail.com>