Re: Trig Simplifications
- To: mathgroup at smc.vnet.net
- Subject: [mg3704] Re: Trig Simplifications
- From: hohmuth at cipserv1.physik.uni-ulm.de (Lars Hohmuth)
- Date: Wed, 10 Apr 1996 02:10:51 -0400
- Organization: Uni Ulm
- Sender: owner-wri-mathgroup at wolfram.com
In article <4ka54g$sai at dragonfly.wolfram.com> Alexander Casti <arc at carmen.phys.columbia.edu> writes: >From: Alexander Casti <arc at carmen.phys.columbia.edu> To: mathgroup at smc.vnet.net >Subject: Trig Simplifications >Date: 8 Apr 1996 04:36:32 GMT >Basically my question is how to get mathematica to write >Exp[I x] in place of Cos[x] + I Sin[x] >Suppose I have the expression >In[1]: f[x_]= Cos[x] + I Sin[x] - Cos[2 X] + I Sin[2 X] >I would like mathematica to simplify this into >f[x_]= Exp[I X] - Exp[2 I X] >I tried the substitution command >In[2]: % ./ Cos[X]+I Sin[X]-> Exp[I X] and it returned >Out[2]: E^{I X} - Cos[2 X] + I Sin[2 X] >So, it seems as though this simple minded approach is not >enough for mathematica to understand the substitution rules >for powers of complex exponentials other than the one I >explicitly gave. >In addition, commands like Simplify[Blah] do not seem to do >the trick either. I believe I have the trigonometry package >loaded in (via the command Needs["Algebra`Trigonometry`"]). >What must I do ? >Thanks for your time. >Alex If you have the Trigonometry package loaded, try the command TrigToComplex[Cos[x] + I Sin[x]]. CU, Lars ==== [MESSAGE SEPARATOR] ====