Sine

Sine is one of the basic trigonometric functions, originally defined for an acute angle in a right triangle as the ratio of the length of the opposite side to the length of the hypotenuse. It extends to all real and complex arguments through the unit circle, where the sine of an angle is the y-coordinate reached by rotating from the positive x-axis, and through its power-series and exponential definitions. The sine function is periodic with period 2 pi, bounded between -1 and 1, and odd, and it is fundamental to the study of periodic phenomena such as sound waves, oscillations and Fourier analysis. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/