Re: Question about trig simplify
- To: mathgroup at smc.vnet.net
- Subject: [mg71131] Re: Question about trig simplify
- From: "dimitris" <dimmechan at yahoo.com>
- Date: Thu, 9 Nov 2006 03:37:39 -0500 (EST)
- References: <eisgno$ngg$1@smc.vnet.net>
You could say it is a feauture; not a bug (at least for me).
Anyway Mathematica offers many opportunities for proper/desired
simplifications/factorizations. It just needs to search a little more.
TrigReduce /@ {-2*Sin[a]*Cos[a], 2*Sin[a]*Cos[a]}
{-Sin[2*a], Sin[2*a]}
Execute the following commands for more information
FrontEndExecute[{HelpBrowserLookup["MainBook","3.3.7"]}]
r = {{Cos[a], Sin[a]}, {-Sin[a], Cos[a]}};
r . r
{{Cos[a]^2 - Sin[a]^2, 2*Cos[a]*Sin[a]}, {-2*Cos[a]*Sin[a], Cos[a]^2 -
Sin[a]^2}}
TrigReduce[%]
{{Cos[2*a], Sin[2*a]}, {-Sin[2*a], Cos[2*a]}}
TrigReduce[r . r . r]
{{Cos[3*a], Sin[3*a]}, {-Sin[3*a], Cos[3*a]}}
Regards
Dimitris