Re: Finding an exponent?
- To: mathgroup at smc.vnet.net
- Subject: [mg112375] Re: Finding an exponent?
- From: David Bailey <dave at removedbailey.co.uk>
- Date: Sat, 11 Sep 2010 05:45:16 -0400 (EDT)
- References: <firstname.lastname@example.org>
On 10/09/10 09:50, AES wrote: > Given Exp[ expr ] where expr is some complex expression in Standard > form, how can I get expr itself in an Input cell? (Preferably > unevaluated, and other than using manual Copy and Paste). > > Log[Exp[expr]] doesn't seem to do it. > 1. Presumably you realise that Log is a multivalued function (you can always add one or more multiples of 2 Pi I to the answer). 2. Since this expression was presumably the result of an evaluation, it shouldn't evaluate any further if you strip the Exp off it. To ignore the multivalued nature of Log, just use PowerExpand. Alternatively, you could decide that you are doing a structural, rather than mathematical operation (as you would be if you used copy/paste) and use Part[Exp[expr], 2] David Bailey http://www.dbaileyconsultancy.co.uk