Even  and Odd Function

A function  is even if for any  in the domain of  we have . Note that this means the domain of  must be symmetric about 0, since  must be in the domain whenever  is. An  even function is symmetric with respect to the vertical (y) axis.

A function  is odd if for any  in the domain of  we have . Note that this means that the domain of  must be symmetric about 0, since  must be in the domain whenever  is. An odd function is symmetric with respect to the origin.