The graphs of \(y = \sin{\theta}\) and \(y = \cos{\theta}\) can be plotted. The graph of \(y = \sin{\theta}\) has a maximum value of 1 and a minimum value of -1. The graph has a period of 360°.

This circle has the centre at the origin and a radius of 1 unit. The point P can move around the circumference of the circle. At point P the \(x\)-coordinate is \(\cos{\theta}\) and the \(y ...

cos(θ) is the x-coordinate of the point P and, sin(θ) is the y-coordinate of the point P. This applet shows how the graphs of sin(θ) and cos(θ) follow directly from the definition of these functions.