Re: Abs and derivative problems
- To: mathgroup at smc.vnet.net
- Subject: [mg14661] Re: Abs and derivative problems
- From: "Allan Hayes" <hay at haystack.demon.co.uk>
- Date: Sat, 7 Nov 1998 02:10:14 -0500
- References: <71q9qu$j25@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
sylvan wrote in message <71q9qu$j25 at smc.vnet.net>...
>I could not calculate the modulus of a complex expression containing
>imaginary parts in both denominator and numerator with Mathematica. An
>Example:
>
>(a + I b) / (c + I d)
>
>a,b,c,d (real) symbolic variables.
>
>.................
sylvan:
ComplexExpand[Abs[(a + I b)/(c + I d)], TargetFunctions -> {Re, Im}]
Out[20]=
Sqrt[a^2 + b^2]/Sqrt[c^2 + d^2]
Allan
---------------------
Allan Hayes
Mathematica Training and Consulting
www.haystack.demon.co.uk
hay at haystack.demon.co.uk
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