A set that is not convex is called a non-convex set. A polygon that is not a convex polygon is sometimes called a concave polygon, and some sources more generally use the term concave set to mean a non-convex set, but most authorities prohibit this usage.
In either case you don't need to deal with the absolute value. A rectified sine wave is a periodic signal with a period equal to half of the full sinusoid, I would write the sine in exponential form and integrate over one period to find the series coefficients.
Period of a Wave. The wave travels through a medium that produce vibration in the medium. Thus, they travel through vibrations from one side to another side. The properties of wave are described by using some terms like wave frequency, wave number, wavelength, its time period, and velocity.eriod of a Sine Wave. The wave motions of several phenomenons are sine waves or sinusoidal waves. That is when an object is rotating around a point, the height of the object at any time is the sine function of the angle made by the object with positive x-axis.