Re: exponential rule application
- To: mathgroup@smc.vnet.net
- Subject: [mg11251] Re: exponential rule application
- From: Paul Abbott <paul@physics.uwa.edu.au>
- Date: Wed, 4 Mar 1998 01:39:12 -0500
- Organization: University of Western Australia
- References: <6cn9pn$bg6@smc.vnet.net>
John Albert Horst wrote:
> I'm trying to compute the following exponential of a matrix with
> elements that are constants:
>
> A={{0,1},{-1,0}};
> MatrixExp[A*t]
>
> The answer can be shown to be {{Cos[t], Sin[t]},{-Sin[t],Cos[t]}} by
> using the definition of the matrix exponential and expanding a few
> terms in the series. However, MatrixExp[A*t]//Simplify returns the
> following expression:
How about
In[1]:= A={{0,1},{-1,0}};
In[2]:= MatrixExp[A*t]//Expand//ComplexExpand Out[2]= {{Cos[t], Sin[t]},
{-Sin[t], Cos[t]}}
Cheers,
Paul
____________________________________________________________________
Paul Abbott Phone: +61-8-9380-2734
Department of Physics Fax: +61-8-9380-1014
The University of Western Australia Nedlands WA 6907
mailto:paul@physics.uwa.edu.au AUSTRALIA
http://www.pd.uwa.edu.au/~paul
God IS a weakly left-handed dice player
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