Re: Getting Symbolic Real and Imag Parts? (Once Again)
- To: mathgroup at smc.vnet.net
- Subject: [mg33504] Re: Getting Symbolic Real and Imag Parts? (Once Again)
- From: adam.smith at hillsdale.edu (Adam Smith)
- Date: Sun, 24 Mar 2002 01:43:58 -0500 (EST)
- References: <a7cs6t$hv8$1@smc.vnet.net> <a7eu4h$mss$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Try the following:
In[19]:=
zComplex = ComplexExpand[Sin[a + I*b], TargetFunctions -> {Re, Im}]
realz = ComplexExpand[Re[zComplex]]
imz = ComplexExpand[Im[zComplex]]
Out[19]=
Cosh[b]*Sin[a] + I*Cos[a]*Sinh[b]
Out[20]=
Cosh[b]*Sin[a]
Out[21]=
Cos[a]*Sinh[b]
In fact you can skip the first step:
In[16]:=
myz = Sin[a + I*b]
realmyz = ComplexExpand[Re[myz]]
imagmyz = ComplexExpand[Im[myz]]
Out[16]=
Sin[a + I*b]
Out[17]=
Cosh[b]*Sin[a]
Out[18]=
Cos[a]*Sinh[b]
Adam Smith
Rodney Sparapani <rsparapa at mcw.edu> wrote in message news:<a7eu4h$mss$1 at smc.vnet.net>...
> aes
>
> Try Im[zComplex] which gives Im[Cosh[b] Sin[a]]+Re[Cos[a] Sinh[b]]
>
> That looks a little strange until you realize that the Im[] portion
>
> is 0 if a and b are real, i.e. Mathematica doesn't assume anything.