Given that the largest proportion of fuel is mixed in to run richly, so as to provide a heat sink to slow and cool the combustion (there was a reason we added lead and/or MTBE to gasoline) to prevent knock or melting the engine, we are effectively throwing out half the gas unburned, or rather, spewing it out in a deliberately inefficient fashion. Now, we could (and have) inject other liquids in with the fuels, but they do bring their own problems, not the least of which is having to maintain two consumables tanks.

Grapher is the "version" of Graphing Calculator that currently ships with Snow Leopard, I don't know if it's too clumsy for quick transcription. As for TeX based stuff... I gave up in-line typesetting in the eighties for both proper layout and old-school word processing... *shudder*.