I do a lot of computer programming and often times i have a very clear idea of a function i need to model something, but i have no idea what kind of function would be good to model it, or how to vary its parameters to get what i need etc. what i need is some way to sketch the function using just mouse or something, and a program that would tell me what kind of function would best approximate what I had in mind. for example, exponential, polynomial, tan inverse, some combination of those? Does anyone know of a program/procedure that does something like this? Math forum is the best place i could find for this, i'm sorry if its not an exact fit.