RE: COLLECT and application of various commands to each coefficient

• To: mathgroup at smc.vnet.net
• Subject: [mg21247] RE: [mg21135] COLLECT and application of various commands to each coefficient
• From: "Ersek, Ted R" <ErsekTR at navair.navy.mil>
• Date: Mon, 20 Dec 1999 02:28:07 -0500 (EST)
• Sender: owner-wri-mathgroup at wolfram.com

Blimbaum Jerry  wrote:
-------------------------------

I want to simplify a long expression using the Collect command.  I
notice that it allows you to apply a command to each of the coefficients,
e.g.

Collect[expr,{Cos[x],Sin[x]},Simplify]

But Simplify here applies to both coefficients.  What if I want to
do different things with each coefficient, e.g.

Collect[expr,{Cos[x],Sin[x]},{Collect coefficient of Cos[x] in terms
of x^2,Simplify Coefficients of Sin[x]]}]

Can this be done within the Collect command?

-------------------------------

The line below should help a lot.
Notice I use (lhs:>rhs) instead of (lhs->rhs).
If (lhs->rhs) is used any value assigned to (c1) is used in Simplify[c1].
For more on this subject down load the files at:
http://www.mathsource.com/cgi-bin/msitem?0210-609

In[12]:=
Collect[expr,{Cos[x],Sin[x]}]/.(c1_ Sin[x]:>Simplify[c1]Sin[x])

---------------------------------
Regards,
Ted Ersek

For Mathematica tips, tricks see
http://www.dot.net.au/~elisha/ersek/Tricks.html

• Prev by Date: Re: Reading data.
• Next by Date: Re: maldelbrot set
• Previous by thread: Re: COLLECT and application of various commands to each coefficient
• Next by thread: Inheritance of \$NotebookPath?