If
f is a
periodic function with
period P, the frequency of
f is equal to the inverse of P, or [latex]\frac{1}{\textrm{P}}[/latex].
Educational Note
In the different areas of physics, including music (sound waves), the frequency refers to the number of times that a periodic phenomenon can be reproduced by unit of time or space. In the case of a periodic function, the unit considered is the one used on the
x-axis of a Cartesian plane.

Here, the period is 4π and the frequency is equal to [latex]\dfrac{1}{4\pi}[/latex], which is approximately 0.08. This means that, over an axis length of 1 unit, the graph of
f covers about 8% of a cycle.