Re: ComplexExpand (V4.0)
- To: mathgroup at smc.vnet.net
- Subject: [mg20374] Re: ComplexExpand (V4.0)
- From: "Allan Hayes" <hay at haystack.demon.co.uk>
- Date: Sun, 17 Oct 1999 02:45:46 -0400
- References: <7u7rm9$p3h@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Blimbaum Jerry DLPC <BlimbaumJE at ncsc.navy.mil> wrote in message news:7u7rm9$p3h at smc.vnet.net... > Why does ComplexExpand[Re[1/(x + I y)]] return > > x/Abs[x+ I y]^2 > > rather then x/(x^2+y^2) > > The Mathematica manual says that ComplexExpand assumes that the > variables are real. > > thanks. jerry blimbaum NSWC Panama City, Fl > Jerry, The answer is correct under the assumption that x and y are real , but I'm not sure why Absolute is allowed, We do have ComplexExpand[Re[1/(x + I y)], TargetFunctions -> {Re}] x/(x^2 + y^2) Allan --------------------- Allan Hayes Mathematica Training and Consulting Leicester UK www.haystack.demon.co.uk hay at haystack.demon.co.uk Voice: +44 (0)116 271 4198 Fax: +44 (0)870 164 0565