tl;dr: Looking for a java library to solve equations. Suggestions welcome.
I'm looking to write an app for the sake of writing an app.
I figured that, as a firmware guy with minimal EE hardware training, a good practice app would be one that acts as a helper for EE projects. One of the things I wanted to add was an equation solver for things like Resistor/Capacitor rate of discharge, etc.
But it's not enough to solve for the same variable over and over. I'd like to choose a known function, then be able to plug in the known values and get back the unknown value, whichever variable it may be. Something like http://hyperphysics.phy-astr.gsu.edu/hbase/electric/capdis.html
At first I looked into Functional Programming, but I'm not sure it's the right way to go.
Digging around Wikipedia, I found Constraint Programming (using linear/float variables) which seems close to what I'm looking for but not quite either. It'd be nice to put in an equation once without having to hash through every derivation.