canonical mathematical expression represenation?

*To*: mathgroup at smc.vnet.net*Subject*: [mg52484] canonical mathematical expression represenation?*From*: nospam nospam <nospam_please at nospam.com>*Date*: Mon, 29 Nov 2004 01:22:31 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

I noticed that Mathematica represents expressions with some specific 'way' or order. For example, Sum[a^k, {k, 0, M}] gives -1 + a^(1+M) ------------- -1 + a How can I make it display the expression, in what I would consider a more 'natural' way, as follows 1 - a^(1+M) ------------- 1 - a I am sure there is a way to do, and why do you think Mathematica does it the way it does? what is the logic of how it represents things? is there a command to convert the first output to the second? I tried few commands, but can not figure it out. thank you, --nospam