Periodic Functions at a Glance


When a function has values that repeat and repeat over and over (like Macbeth and his obsession with tomorrow and tomorrow and . . .), it's a periodic function.

Newsflash: all the trig functions are periodic. Let's see what sine and cosine look like when we slap 'em onto a graph.

Example 1

Graph y = -sin x.


Example 2

Graph y = 0.5 sin x.


Example 3

Graph y = -2 cos x.


Example 4

Graph y = cos(½x).


Example 5

Graph y = 2cos(2x).


Exercise 1

Given y = 10cos(4x), find the amplitude.


Exercise 2

Given y = 3cos(4x), find the period.


Exercise 3

Given find the amplitude.


Exercise 4

Given find the period.