Coincidence sinus
--- Introduction ---
This is a graphic exercise: it presents to you the graph of a sinusoidal
function (either under the form of Acos(x+B) or under the form of
Acos(x)+Bsin(x)), and asks you to find back this function, And you can make
several tries, each try giving you a graphical comparison between your reply
and the given graph, allowing you to improve your reply.
At the end of the tries, you will be given a score according the the
deviation of your best try. And the following configuration parameters allow
variation of the style and the difficulty level of the exercise.