I have made a Formula Calculator for MacOSX that I am giving away for free for anyone interested in Math.
I have made a short Video presentation of it: http://youtu.be/xURq1wd1uQ8
(Best is to view in full-screen or larger view. Resolution at least 480p).
Choose english captions on the "cc" button in youtube.
The calculator can be downloaded on my site: FORMULA CALCULATOR
Anyone have comments on it, just tell me.