[Date Index] [Thread Index] [Author Index]

Re: Inverse of function

• To: mathgroup at smc.vnet.net
• Subject: [mg121420] Re: Inverse of function
• From: "Oleksandr Rasputinov" <oleksandr_rasputinov at hmamail.com>
• Date: Wed, 14 Sep 2011 05:16:07 -0400 (EDT)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com
• References: <j4neqn$54e$1@smc.vnet.net>

On Tue, 13 Sep 2011 12:29:27 +0100, Berthold Hamburger  
<b-hamburger at artinso.com> wrote:

> Hi,
>
> I stumbled over a small riddle using mathematica 8. Asking for the
> inverse of the function f(x)= x^2, I receive the solution: f^(-1)(x)
> = =C2=B1sqrt(x)
>
> Why is that so? I had rather expected an error message.
>
> Regards
>

Perhaps this is a result of the particular way in which you asked, or some  
assumptions inadvertently applied? In a new session, InverseFunction  
behaves as expected:

In[1] := InverseFunction[#^2 &]

During evaluation of In[1] := InverseFunction::ifun: Inverse functions are  
being used. Values may be lost for multivalued inverses.

Out[1] = -Sqrt[#1] &