Increasing and decreasing functions
A function of 
increasing
if 
, 
for all 
of the region definitions (with the increase of the argument the corresponding points of the graph ascending stems)
The function of the descending
if , 
for all of the region definitions (with the increase of the argument the corresponding points of the graph omitted)
Even and odd functions
Function even
for all 
of the region definitions. The graph of an even function is symmetrical to the axis vanocni 
A function is odd
for all of the region definitions. The graph of an odd function is symmetric vanocni the origin.
The frequency
Definition: a Function is called periodic with period 
if for any of the determining function of the number and 
also belong to the scope and the validity of the equation
.
Through the gaps in length 
of the graph of a periodic function repeats itself.
Period features 
Functions 
have period 
.
Functions 
have period 
.