If

*f*is a periodic function with period P, the frequency of*f*is equal to the inverse of P, or \(\frac{1}{\textrm{P}}\).### 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 \(\dfrac{1}{4\pi}\), 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.