Re: TrigExpand - Odd behavior

*To*: mathgroup at smc.vnet.net*Subject*: [mg55427] Re: TrigExpand - Odd behavior*From*: dh <dh at metrohm.ch>*Date*: Wed, 23 Mar 2005 05:34:38 -0500 (EST)*References*: <d1on7b$nda$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Bob Stagat wrote: > Try executing the following three lines and explain the last result... > > Cos[45 Degree] > > Cos[x+45 Degree] > > Cos[x+45 Degree]//TrigExpand > > Thanks... > ~ BS ~ > Hello Bob, "Degree" has an accurate value of 180/Pi. Mathematica will not replace accurate expressions by expressions having machine precision. Therefore: Sin[1 Degree] will not evaluate, however this will: Sin[45 Degree] because there is a closed form accurate answer. Also the following will evaluate: Sin[1. Degree] because 1. Degree has machine precission. Your output looks rather strange because Degree is printed by a small o. This may look bizare, but it still means 180/Pi. Daniel