Even Function

Author

Eric W. Weisstein
January 15, 2006

This notebook downloaded from http://mathworld.wolfram.com/notebooks/Calculus/EvenFunction.nb.

For more information, see Eric's MathWorld entry http://mathworld.wolfram.com/EvenFunction.html.

©2006 Wolfram Research, Inc. except for portions noted otherwise

Code

EvenFunctionQ[f_]:=Module[{x},f[x]-f[-x]===0]

Examples

fs={1&,Abs,Cos,#^2&,Exp[-#^2]&};

EvenFunctionQ/@fs

<<Utilities`Typesetting`

Show[GraphicsArray[Partition[MapIndexed[Plot[#1,{x,-6,6},PlotRange->All,DisplayFunction->Identity,
AxesLabel->TraditionalForm/@{x,#1},PlotStyle->{Red,Orange,Green,Blue,Purple}[[#2[[1]]]]]&,Through[fs[x]]],3,3,{1,1},{}]],ImageSize->500]