Re: Solving complex equations

*To*: mathgroup at smc.vnet.net*Subject*: [mg91222] Re: Solving complex equations*From*: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>*Date*: Sat, 9 Aug 2008 07:50:01 -0400 (EDT)*Organization*: The Open University, Milton Keynes, UK*References*: <g7h9m1$b6e$1@smc.vnet.net>

Adel Elsabbagh wrote: > If I have a complex equation in the form of > a+b I + c+d I == 3+ 4 I > where a, b, c, and d are all assumed to be real. > > How do I tell Mathematica 6 to separate the real and imaginary parts to make > two equations in the form of > a + c == 3, and > b + d == 4. > > I need this to apply it on a long list of equations. A possible approach could be the following thought it might need some tweaking depending on the actual structure of your equations. expr = a + b I + c + d I == 3 + 4 I; Thread[ComplexExpand[expr] /. Plus[r___, Times[Complex[0, 1], Plus[i___]]] :> {Plus[r], i} /. Complex[a_, b_] -> List[a, b]] {a + c == 3, b + d == 4} Regards, -- Jean-Marc