Even and Odd Functions

Even functions are functions for which the left half of the plane looks like the mirror image of the right half of the plane. Odd functions are functions where the left half of the plane looks like the mirror image of the right half of the plane, only upside-down.

Mathematically, we say that a function f(x) is even if f(x)=f(-x) and is odd if f(-x)=-f(x).

Some examples:

Some even functions	Some odd functions
f(x) = |x|	f(x) = 1/x
f(x) = x2	f(x) = x3
f(x) = cos(x)	f(x) = sin(x)