About

Available on the App Store

Purpose

At my workplace, in my desk drawer, among pencils, pens, and paper clips, I keep a small screwdriver and a small pair of pliers. Nothing fancy (certainly, not even comparable to a full set of tools in my garage!) and I don't even use these tools every day, but they are there when I need them. Today, for example, the screwdriver came quite handy when I was fixing a broken microwave oven in my company's kitchen. :)

I designed the Calculator of Formulas with Graphing app to be like this small screwdriver. When I am at my office computer, I have plenty of sophisticated math and graphing tools at my disposal. But when the only computer within my reach is my trusty iPhone (or iPad), this app is right there for a quick check of numerical results and graphs produced by a formula (function) needed at the moment. What distinguishes this app from many other RPN calculators available at the App Store? Some of them allow for formula coding, do graphs, and are free, too. Up to date, frustratingly, most of these apps feature formulas of only one variable. In most real life applications, however, mathematical formulas have multiple variables! This app does all of the above plus the following:

    1. Programs mathematical formulas with up to six variables.
    2. Is simple to use.
    3. Plots graphs with respect to a chosen single variable while keeping all other variables fixed.
    4. Plots graphs when all the variables are changing along a user-prescribed vector. This relatively new concept of "ray plotting" enables user to probe a function in n dimensions by looking at its 1-dimensional slices.
    5. Does graph tracing and enables graph manipulation with a simple set of intuitive touch gestures instead of button/pop up controls.
    6. Saves most used formulas along with detailed description for later use.
    7. Creates tables of calculated results that can be pasted into other applications.
    8. Has an exhaustive set of help files and tutorials.

Other tabs in this page contain full tutorial and manual for you to learn how to use it.

History

In February 2012, out of the blue, I decided to learn how to develop iOS apps - a hobby I could pursue in so-called spare time after work. I bought a Mac computer, a few books, and downloaded Xcode 4 from the Apple website. In my search for more educational material, I discovered on iTunes University an awesome (and free!) set of lectures titled "iPad and iPhone Application Development" by Paul Hegarty and his coworkers from Stanford University. The first three homework assignments in this course were about a Reverse Polish Notation calculator with graphing function. This, in turn, sparked the idea of what my first app for iPhone would be. In May, after working on and off in my spare time doing gazillions of additions, deletions, and tweaks, I had the fully working version. Since I found it quite useful, a thought occurred to me: Why not share this app with the rest of the world, for free and without ads? This, however, required many weeks of adding the help system, including a tutorial, during which I learned a lot of additional coding tricks.

In summary, this app is an evolved homework project. :)

Acknowledgement

I am greatly indebted to a few gentlemen who graciously agreed to test this app: Michael Lawless, Wenkel Liang, Adam Fraczkiewicz, and Adam Lee. A huge "thank you" goes to Paul Hegarty, his co-lecturers, and Stanford University for providing the inspiring lectures on app development. I thank Google for this wonderful web hosting service. Finally, nothing of this would be possible without all the great people of Apple, Inc., especially Steve Jobs and Steve Wozniak who started the whole ball rolling.

Robert Fraczkiewicz