Re: how to solve this problem?
- To: mathgroup at smc.vnet.net
- Subject: [mg95107] Re: [mg95059] how to solve this problem?
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Tue, 6 Jan 2009 04:13:54 -0500 (EST)
- Reply-to: hanlonr at cox.net
Clear[x, y];
z = x + I*y;
Assuming[{Element[{x, y}, Reals]}, Simplify[Re[z]]]
x
Assuming[{Element[{x, y}, Reals]}, Simplify[Im[z]]]
y
Or something like
Clear[defineReal];
SetAttributes[defineReal, Listable];
defineReal[x_Symbol] := Module[{},
x /: Re[x] = x;
x /: Im[x] = 0;]
defineReal[{x, y}];
Re[z]
x
Im[z]
y
Bob Hanlon
On Mon, Jan 5, 2009 at 7:05 AM , Ising wrote:
> Hi:
> I want to define the variables x and y are real at first,then:
> z=x+I*y;
> Re[z]=x
> Im[z]=y
> Using "Assumptions" "Assuming"? But i don not know how to use it. Is
> there other ways to get that?
> I know in another system, it is easy, as in
> assume(x,real,y,real); So what is in Mathematica?
> Thanks!