Overview
Here is a typical sinusoid:
The most general mathematical formula for a 
sinusoid is
\(x(t)=A \cos(2 \pi f_0 t + \phi)\)
The goal of this demo is to learn how to sketch a sinusoid given 
its formula and to write the formula of a sinusoid given its plot.
Tutorial
Here is a quick tutorial on how to 
sketch a plot from an equation, and
here is a tutorial on going the other way. 
MATLAB
Here is how to plot sines in MATLAB.
Sine Drill
This will take you to 
MATLAB 
GUI (graphical user interface) that tests your 
ability to go from plots of cosine waves to equations.