This is documentation for Mathematica 3, which was
based on an earlier version of the Wolfram Language.
View current documentation (Version 11.2)
 Documentation / Mathematica / Built-in Functions / Mathematical Functions / Numerical Functions  /
Re

  • Re[ z ] gives the real part of the complex number z.
  • Re[ expr ] is left unevaluated if expr is not a numeric quantity.
  • See the Mathematica book: Section 1.1.5Section 3.2.2.
  • See also: Im, Abs, Arg, ComplexExpand.

    Further Examples

    This extracts the real part of this complex number.

    In[1]:=

    Out[1]=

    Since either a or b might be complex, Re doesn't evaluate to b.

    In[2]:=

    Out[2]=

    ComplexExpand assumes the variables a and b are real.

    In[3]:=

    Out[3]=