The sin(α) function is a trigonometric functions whose values are between -1 and 1. So for all α in [0°; 360°]: -1 ≤ sin(α) ≤ 1 is always true.

The sin function can be seen in the unit circe:

The value of sin(30°) is the length of the purple side of the triangle, in this particular case 0,5.

In a right triangle the equation sin(α) = opposite leg / hypotenuse always holds. In case of the unit circle the length of the hypotenuse of the triangle is always 1. So sin(α) = opposite leg.

Some important angles:

sin(0°) = 0

sin(30°) = 0,5

sin(90°) = 1

sin(180°) = 0

sin(270°) = -1

sin(360°) = 0

The sin(α) function can also be displayed in a coordinate system, shown in the picture below.

As a Code Example we can try to paint a sin function.