Re: Difficulties with Re
- To: mathgroup at smc.vnet.net
- Subject: [mg98326] Re: [mg98349] Difficulties with Re
- From: Curtis Osterhoudt <cfo at lanl.gov>
- Date: Wed, 8 Apr 2009 02:43:19 -0400 (EDT)
- Organization: LANL
- References: <200904060905.FAA26352@smc.vnet.net>
- Reply-to: cfo at lanl.gov
On Monday 06 April 2009 03:05:13 am Aaron Fude wrote: > Assuming[x > 0 && y > 0, Re[Exp[x + I y]] // Simplify] > Assuming[x > 0 && y > 0, Re[Exp[(x + I y)^2]] // Simplify] Hi, Aaron, If you check the expansion of the second expression, you'll notice that it contains a part proportional to Exp[2ix*y]. This is generally complex for x>0 and y>0; if x*y is an integer multiple of pi, then the entire expression reduces to a real number; otherwise, the whole expression is imaginary. Unless you provide Mathematica (or anyone) more constraints on x and y, there is no way to tell you whether the whole thing has a real part, or whether the real part is zero. -- ================================== Curtis Osterhoudt cfo at remove_this.lanl.and_this.gov PGP Key ID: 0x4DCA2A10 ==================================
- References:
- Difficulties with Re
- From: Aaron Fude <aaronfude@gmail.com>
- Difficulties with Re