- number - The angle in radians for which you want the sine.
The SIN function returns the sine of an angle provided in radians. In geometric terms, the sine of an angle returns the ratio of a right triangle's opposite side over its hypotenuse. For example, the sine of PI()/6 radians (30°) returns the ratio 0.5.
=SIN(PI()/6) // Returns 0.5
To supply an angle to SIN in degrees, multiply the angle by PI()/180 or use the RADIANS function to convert to radians. For example, to get the SIN of 30 degrees, you can use either formula below:
The graph of sine, shown above, visualizes the output of the function for all angles from 0 to a full rotation. The function is periodic, so after a full rotation, the output of the function repeats. Geometrically, the function returns the y-component of the point corresponding to an angle on the unit circle. The function's output will always be in the range [-1, 1].
Graph courtesy of wumbo.net.