Re: ComplexExpand
- To: mathgroup@smc.vnet.net
- Subject: [mg12296] Re: [mg12275] ComplexExpand
- From: MJE <evans.nospam@gte.net>
- Date: Thu, 7 May 1998 18:51:32 -0400
- Organization: None
- References: <199805050730.DAA17212@smc.vnet.net.>
Jack, I think your package is great and something like it should be part of the product. In the distant past I have given thought to these issues. Here is my contribution. In general terms, it is difficult to work with Mathematica while trying to keep it advised that certain symbols are real. In particular, Mathematica makes it extremely difficult to work with complex exponentials in which all symbols in the exponent are known to be real numbers (except the imaginary unit itself, of course). Such exponentials are common. In my experience, they are more common than any other kind of complex exponential. ComplexExpand is fine, but I recall it always reducing me down to trig functions and thrashing my clean exponential forms. Conjugate[Exp[I*x]] should not be so hard when x is real! Half the reason to use complex exponentials in the first place is to avoid using trig functions, because the polar form encapsulates both magnitude and phase very compactly and makes algebraic manipulations simple. These nice features seem to vanish in Mathematica. Maybe I just did not exploit ComplexExpand as fully as I should have, or perhaps there are other features like Assumptions that I have not used enough to know how they apply to this problem. My idea then is to implement some extensions which enable one to work with complex exponentials having real parameters. Best regards, Mark Evans
- References:
- ComplexExpand
- From: Jack Goldberg <jackgold@math.lsa.umich.edu>
- ComplexExpand