Re: Inverse of function
- To: mathgroup at smc.vnet.net
- Subject: [mg121413] Re: Inverse of function
- From: Simon <simonjtyler at gmail.com>
- Date: Wed, 14 Sep 2011 05:14:51 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <j4neqn$54e$1@smc.vnet.net>
- Reply-to: comp.soft-sys.math.mathematica at googlegroups.com
Exactly what code did you use to get the inverse function?
In[1]:= f[x_] := x^2
In[2]:= InverseFunction[f][y]
During evaluation of In[9]:= InverseFunction::ifun: Inverse functions are being used. Values may be lost for multivalued inverses. >>
Out[2]= -Sqrt[y]
Of course, Solve, Reduce and WolframAlpha are a bit smarter than that
In[3]:= Solve[f[x] == y, x]
Out[3]= {{x -> -Sqrt[y]}, {x -> Sqrt[y]}}
In[4]:= WolframAlpha["inverse of f(x) = x^2", {{"Result", 1}, "Plaintext"}]
Out[4]= "f^(-1)(x) = \[PlusMinus]sqrt(x)"