Love the slider bars. They really show how the graph changes for each parameter. Checked against a few quadratics and it appears to be working fine.
If it ain't broke, fix it until it is.
A number by itself is useful, but it is far more useful to know how accurate or certain that number is.
Woah that is cool!!
I would love you if you created a function grapher, you know, graphing y=x y=e^x .....