Re: Complex Number Simultaneous Equation 2 Unknowns

*To*: mathgroup at smc.vnet.net*Subject*: [mg31534] Re: Complex Number Simultaneous Equation 2 Unknowns*From*: "Avraham Shinnar" <as1619 at columbia.edu>*Date*: Fri, 9 Nov 2001 06:13:43 -0500 (EST)*Approved*: Steven M. Christensen <steve@smc.vnet.net>, Moderator*Organization*: Columbia University*References*: <9sdnp2$6gs$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

The primary problem wich is causing the error, is the use of =. = means assignment, == means a test for equality. The FullForm of [((2 + 4\[ImaginaryI])*a) + ((1 + \[ImaginaryI])*b) is: Plus[Times[Complex[2, 4], a], Times[Complex[1, 1], b]]. So you are trying to assign something to the Plus function, which is protected. Some other problems: if you want to specify more then one equation, you have to either put them in a list, or use and (&& or \[And]) to combine them. option 1) Solve [{((2 + 4\[ImaginaryI])*a) + ((1 + \[ImaginaryI])*b) == (118 + 24\[ImaginaryI]), ((1 + \[ImaginaryI])* a) + ((3 + \[ImaginaryI])* b) == (110 + \[ImaginaryI]0)}, {a, b}] option 2) Solve [((2 + 4\[ImaginaryI])*a) + ((1 + \[ImaginaryI])*b) == (118 + 24\[ImaginaryI]) && ((1 + \[ImaginaryI])* a) + ((3 + \[ImaginaryI])* b) == (110 + \[ImaginaryI]0), {a, b}] note: you also accidenly used curly braces where you did not mean to: {110 + \[ImaginaryI]0}. These should be replaced by parenthesis (as i did). In general () are used to specify the order of operations, {} delineate a list, and [] is used for a function application: f[x]. If you want to enter a \[ImaginaryJ], type in esc jj esc. note that output will still contain \[ImaginaryI]), since internally they are both Complex[0, 1], and \[ImaginaryI]) is the default output form of this. "Removethisspamtrap_Martin Evans_ and this one too" <mcemail at dial.pipex.com> wrote in message news:9sdnp2$6gs$1 at smc.vnet.net... > I've a simultaneous linear equation with complex numbers i'd like to > put through Mathematica (I'm assuming this is possible!) > > > > Solve [((2 + 4\[ImaginaryI])*a) + ((1 + \[ImaginaryI])*b) = (118 + > 24\[ImaginaryI]), > > ((1 + \[ImaginaryI])* a) + ((3 + \[ImaginaryI])* > b) = {110 + \[ImaginaryI]0}, > > {a, b}] > > (all on one line but split for some sort of clarity here) > > > I get this as the output: > > Set::"write": "Tag \!\(Plus\) in \!\(\(\(\(\((2 + \(\(4\\ \ > \[ImaginaryI]\)\))\)\)\\ a\)\) + \(\(\(\((1 + \[ImaginaryI])\)\)\\ > b\)\)\) is \ > Protected." > > Set::"write": "Tag \!\(Plus\) in \!\(\(\(\(\((1 + \[ImaginaryI])\)\)\\ > a\)\) \ > + \(\(\(\((3 + \[ImaginaryI])\)\)\\ b\)\)\) is Protected." > > General::"ivar": "\!\(110 + \[ImaginaryI]0\) is not a valid variable." > > Solve[118 + 24 \[ImaginaryI], {110 + \[ImaginaryI]0}, {a, b}] > > Any ideas as to what i'm doing wrong as the error messages don't make > it obvious (at least to me as a 4 day old user!!) > > Also I seem to HAVE to use the esc ii esc where i would prefer to use > lower case J (as an electrical eng) is there something special that > needs to be done to use lower case J as in the help files it appears > to be in bold > > > -- >