Sine

Sine is a trigonometric function describing the ratio between the opposite side and the hypotenuse in a right triangle. As a function it is usually abbreviated sin.

Sine Graph

The basic sine graph is as follows:

x values y values 0 0 π/2 1 π 0 3π/2 -1 2π 0

That would be a full period of the graph - as 2π radians is equivalent to one circle. The graph continues in that pattern.

Relationship to cosine and cosecant

A mathematical identity involving sine is:

$\sin \theta =\cos \left({\frac {\pi }{2}}-\theta \right)={\frac {1}{\csc \theta }}\,$