This simulation shows relation between sine/cosine function with tow vectors.
The black vector is a unit vector (with length 1), red arrow represents the cosine function while green arrow represent the sine function.
You can drag both arrows to find out how sine/cosine changes with angle between arrows.

VIEW or DOWNLOAD ejs xml source
then click to translate strings for selected locale.

Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop.