Even and Odd Signals

signal x ( t ) or x[n] is referred to as an even signal if

x ( - t ) = x ( r )
x [ - n ] = x [ n ]

A signal x ( t ) or x[n] is referred to as an odd signal if

Examples of even x ( - t ) = - x ( t ) , x [ - n ] = - x [ n ] and odd signals are shown in pictures