A function is called a simple harmonic function (or, harmonic oscillation) if
Amplitude, period, and phase. The absolute value of represents the largest value (in absolute value) attained by the function , and is called the amplitude of . The interval represents one cycle (or, one complete oscillation), and is called period of . Note that if then is a periodic function with period . is called the phase shift (or, the initial phase) of .
Graph. Each cycle repeats itself for every interval