Lecture 4: Symmetry and Its Effects
Examples of even functions are and . An odd function is a function such that
Examples of odd functions are and . There are several facts about even and odd functions that can help us simplify and interpret some computations.

The product rules:
 even even = even
 even odd = odd even = odd
 odd odd = even.

Integration. When integrating over a symmetric interval about the origin,
Let us use these facts in relation to Fourier series. Suppose we want to compute
the F.S. of an
even
function (such as the square wave signal example).
Then
To compute the F.S. of an
odd
signal,
Review the signals transformed so far in light of these symmetries.