I just want to thank each of you for your help. I ultimately went with the Taylor series expansion method implementing Paul's suggestion to distribute the denominator across the terms.

FYI, this project is a senior design project for mechanical engineering, which is being presented next Tuesday. Though I have been working on it all semester, the last thing to complete was to calibrate the ADC value to a height based on the geometry of the mechanism. All along, I had been planning on a lookup table. But when I wrote it out, it required more space on my microcontroller than I had available.

That's when I started looking at Taylor series. By the time I got around to asking for your help, I was pretty well committed to that route. Given more time, I would probably use a different method, maybe even using a math coprocessor (which I admit I didn't even know existed until only a few days ago).

Now I can breathe a big 'ol sigh of relief knowing that it's done. All I have left to do is put it together on perfboard and put it in the enclosure.

Thanks again,

Jason