A function
is said to be antiperiodic with antiperiod
if
for ,
3, .... For example, the sine function
is antiperiodic with period
(as well as with antiperiods
,
, etc.).
It can be easily shown that if is antiperiodic with period
, then it is periodic with period
. But if
is periodic with period
,
may or may not be antiperiodic with period
.
The constant function has the interesting property of being periodic with any
period
and antiperiodic with any antiperiod
for all nonzero real numbers
.