An application that provides the same functionaly as HP Solve or similar equasion solver in some older Sharp pocket computers.
Alows you to define and name an equasion using variables. Then you 'run' the equasion you're then prompted for each variable. But you can skip one, and Newtons Method is used to calculate the value of the missing variable. I can't even simply emulate this in Excel!
Would be very handy for financial calulations where the 'goal' variable varies depending on the situation.