... >> Precalculus >> Function >> Sinusoidal Function
Definition: Let A, B, C and D be fixed constants, where A and B are both positive. Then we can form the new function: y = A*sin( ((2*pi)/B)*(x - C) ) + D, which is called a sinusoidal function. The four constants can be interpreted graphically as indicated. This is very similar to a periodic function, where they both have values of amplitude and period.
Source: "Precalculus" by David H. Collingwood, K. David Prince, and Matthew M. Conroy at University of Washington
Example: Graph example: http://i.ytimg.com/vi/n5tTAsBJS_g/ 0.jpg