Techy odds and ends

Numerical integration is an operation that many older machines are not able to perform without add-on libraries (e.g. Math Pac for HP-41C) or without writing a program from scratch to do it. There are, of course, some exceptions to this; Hewlett Packard's HP-15C and HP-42S come straight to mind, as does the Casio fx-180P, for example, but these machines are actually the exception, not the rule. There are many methods used to calculate definite integrals, that is integrals between known boundaries yielding a numerical result. One method that is a good trade-off between precision and complexity of application is Simpson's Rule , which attempts to find a quadratic of the form $a\cdot x^2+b\cdot x+c$ that fits or is close to our function. Finding the integral of this polynomial is very easy: \[ \int_{x_1}^{x_2} \! (a\cdot x^2 + b\cdot x + c) \, \partial x = \frac a 3 (x_2^3-x_1^3) + \frac b 2 (x_2^2-x_1^2) + c\cdot (x_2 - x_1) \] Basically, Simpson's Rule states: \[

Now this is something unusual. Who would want to use a 30-year-old machine worth something as a mere egg timer, or use it at all in a kitchen, where it could easily get damaged? It just so happens that one of the machines in my collection is a SwissMicros DM41. It's built really solid and it's basically the same thing as a Hewlett Packard HP-41CX in a case the size of a credit card, so that means that it incorporates, among other things, a Time Module, which gives it a stopwatch, countdown timer and alarm capabilities. The DM41 is a great little piece of technology. However, the operative word here is "little". While its LCD is the same size as it's Voyager-sized big brother, the DM41L, its keys are just a bit too small for the device to be fully practical, but for some things its form factor makes it just right. Okay, it's more than an egg timer. This said, my DM41 gets used most of the time in the kitchen as a timer while I'm cooking. I keep i