Re: Re: A simpl(e)ification
- To: mathgroup at smc.vnet.net
- Subject: [mg105788] Re: [mg105779] Re: A simpl(e)ification
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Sat, 19 Dec 2009 06:25:12 -0500 (EST)
- Reply-to: hanlonr at cox.net
Simplify[Im[E^(-2 I a) b],
Element[{a, b}, Reals]]
(-b)*Sin[2*a]
In the second case, also specify that b is not zero
Simplify[Im[E^(-2 I a) 1/b],
Element[{a, b}, Reals] && b != 0]
-(Sin[2*a]/b)
Bob Hanlon
---- DC <b.gatessucks at gmail.com> wrote:
=============
You might try
In[3]:= ComplexExpand[Im[E^(-2 I a) 1/b], TargetFunctions -> {Re, Im}]
Out[3]= -(Sin[2 a]/b)
-Francesco
On 12/17/2009 12:22 PM, Pianiel wrote:
> Dear All,
>
> With Mathematica 7.0.1, the following expression;
>
> Simplify[ Im[E^(-2 I a) b], Assumptions -> Element[a, Reals]&&
> Element[b, Reals]]
>
> gives
>
> -b Sin[2 a]
>
> But:
>
> Simplify[ Im[E^(-2 I a) 1/b], Assumptions -> Element[a, Reals]&&
> Element[b, Reals]]
>
> gives
>
> Im[E^(-2 I a)/b]
>
> So we see that the Im[] is not simplified. Why?
>
> Any idea how to help mathematica to handle the simplification shown in
> the second example. It seems to be so similar to the first kind...
>
> Thanks in advance
>
> Pianiel
>