Re: TrigExpand - Odd behavior
- To: mathgroup at smc.vnet.net
- Subject: [mg55434] Re: TrigExpand - Odd behavior
- From: <wwolfe18 at comcast.net>
- Date: Wed, 23 Mar 2005 05:34:44 -0500 (EST)
- References: <d1on7b$nda$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
"Bob Stagat" <stagat at linkline.com> wrote in message news:d1on7b$nda$1 at smc.vnet.net... > > 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 ~ Bob, This is just Mathematica insisting on giving exact answers. Put a decimal in somewhere. Cos[x+45. Degree]//TrigExpand gives 0.707107 Cos[x]+I (0. Cos[x]+0. Sin[x])-0.707107 Sin[x] Note the zero imaginary part. Get rid of it with Chop: Cos[x+45. Degree]//TrigExpand//Chop gives 0.707107 Cos[x] - 0.707107 Sin[x] Warren Wolfe Evanston, Il