Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2001
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2001

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

Search the Archive

Re: Definition of an exponential function

  • To: mathgroup at smc.vnet.net
  • Subject: [mg31685] Re: [mg31665] Definition of an exponential function
  • From: BobHanlon at aol.com
  • Date: Sat, 24 Nov 2001 16:43:57 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

In a message dated 2001/11/23 6:45:02 AM, psino at tee.gr writes:

>I want to define a function with the properties of Exp.
>The definition
>f[x_+y_]:=f[x]f[y]
>f[m_  x_]:=f[x]^m
>f[0]=1
>gives
>f[x]^2 f[-x]^2=1
>but
>f[x]^m f[-x]^m=(1/f[x])^m (f[x])^m.
>Is there a way in Mathematica 4.1 to obtain f[x]^m f[-x]^m=1?
>

f[x_+y_]:=f[x]f[y];
f[m_ * x_]:=f[x]^m;
f[0]=1;

Table[f[x]^m * f[-x]^m, {m, -5, 5}]

{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}

Simplify[f[x]^m * f[-x]^m, Element[m, Integers]]

1

f[x]^m * f[-x]^m // PowerExpand

1


Bob Hanlon
Chantilly, VA  USA


  • Prev by Date: Re: binary trees
  • Next by Date: integral function
  • Previous by thread: Definition of an exponential function
  • Next by thread: Split-Step Fourier Method