SOLUTION: Sketch the graph of a wave with a period of 4 and an amplitude of 3. I don't exactly understand how to plot this, and my textbook does not describe this well. Please help!

A (sine) wave starts at the origin (0,0), 
goes up to its maximum,
back down to the x-axis,
down below the x-axis to its minimum,
and back up to the x-axis.

The maximum is the amplitude value.
The minimum is the negative of the amplitude value.
The wave ends on the x-axis at the period value.

Here is your wave:



Edwin