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 ...

As the point P moves anticlockwise round the circle, the values of \(\cos{\theta}\) and \(\sin{\theta}\) change, therefore the value of \(\tan{\theta}\) will change. The graph has a period of 180°.