# How do you find the amplitude and period of y=3 cos pi x?

Oct 13, 2015

Amplitude is 3 units and period is 2 radians.

#### Explanation:

For any general cosine function of the form $y = A \sin B x$,
A represents the amplitude, ie the maximum displacement from the x-axis, and the period is given by $T = \frac{2 \pi}{B}$ and this represents the number of radians required for a full cycle of the graph.

So in this case, the amplitude is 3 and the period is 2.

Graphically :

graph{3cos(pix) [-10, 10, -5, 5]}