User Portlet

I'm a bit over 70 and retired. I started as an engineer in electronics, but migrated to computing and eventually managed the computing center at the Australian Antarctic Division. It has changed quite a lot since I retired.

Since retirement, I've maintained a little interest in electronics and computers and computing, and joined a couple of volunteer groups. I'm not famous and sometimes joke about my "mountain of publications one high" - I've had a few designs published in the Australian hobby magazine: Silicon Chip, and the British magazine: Everyday Practical Electronics, but otherwise I know more people more famous than me than people less famous than me.

I bought Mathematica because I got a bee in my bonnet about politics and the fact that most of our laws, tax is an example, are piecewise linear. I also noticed that a lot of laws could be pounded about to make S-shaped curves and I have the opinion that knees are often more important than maxima and minima, but that might be just another bee in my bonnet. I discovered that S-shaped curves are called Sigmoid curves only after I bought Mathematica.

I'm very much at the trivial, beginner end of the Mathematica user spectrum. I've used it to simplify some Boolean expressions, and to discover that the equation for computing the length of a spiral arc is amazingly complicated.

My current interest and stumbling block is sunrise and sunset. I've found the example that plots the difference, but beating that example into submission to persuade it to plot just sunrise and or sunset has become a tormenting frustration.

To ease that frustration, I've bought quite a lot of CDs of complete symphonies of Mahler and Bruckner and...