Express a complex function $f(z)$ as $u(x,y)+iv(x,y)$

Question

How can I write a complex function $f(z)$ in the form $u(x,y)+iv(x,y)$ using Mathematica? Re and Im do not work, because they do it for complex numbers, not functions. For example, if I try

Re[2 I (z) + 6 Conjugate[(z)] + Sin[(z)]]

Mathematica returns:

-2 Im[z] + 6 Re[z] + Re[Sin[z]]

Previously: Extract real part of a complex expression better than Re does, Does the Im function work with symbolic arguments?, How to simplify my expression to the style of “a+b*I”?. I probably should have searched for duplicates before posting my answer. — , Jul 29 '14 at 02:06

score 4 · Accepted Answer · answered Jul 29 '14 at 01:55

4

Replace z with x + I y and use ComplexExpand.

ComplexExpand[2 I z + 6 Conjugate[z] + Sin[z] /. z -> x + I y]
(* 6 x - 2 y + Cosh[y] Sin[x] + I (2 x - 6 y + Cos[x] Sinh[y]) *)

answered Jul 29 '14 at 01:55

Express a complex function $f(z)$ as $u(x,y)+iv(x,y)$

1 Answers1