"Sign Control" is my motto at Trader Joe's, and finally things are getting back under control as I have returned to work. I'm still coughing, and I'm on antibiotics for a bacterial bronchitis infection. I can never be glad enough that I live in the modern world, at least here in what is generally referred to as the "West." I have been told that I am not contagious but I am still taking precautions not to spread germs. The plague that has been afflicting New England is here in MidAtlantica now, and a co-worker called me during my work hours to report exactly the same wretched symptoms that I suffered about twelve days ago. I'm guessing I won't see him on the job for a while.

Meanwhile I'm back in my studio painting and, of course, doing calculus. If I've recovered enough strength to lift Anton's weighty tome, then I can surely work from it. I am still doing derivatives, a process I am now informed is called differentiation. To quote from the book,

"It is often useful to think of differentiation as an operation which, when applied to a function f, produces a new function f prime. In the case where the independent variable is x, the differentiation operation is often denoted by the symbol d/dx[ ], which is read, the derivative with respect to x of…"

So I have been differentiating, though I don't understand all the derivative problems in the book. Some of them feature neat but non-numbered graphs, where you are supposed to sketch the derivative of that graph's function. And then there's "Show that f(x) is not differentiable at…." Whenever I see the words "Show that…" in a math book, it means you are supposed to crank out a proof using math alone on a piece of paper. Drawing another graph in colored pencil and making some very rough sample calculations to give me a view of the "territory" doesn't count, although that's what I did. I hope for more enlightenment about these graph problems. I would like to do more derivative problems. I must really be getting better from the unpleasantness.

I did notice that after doing a bunch of derivatives from very simple functions, some patterns emerged that I could use to predict what the derivative was going to be without doing the math. As I turn the page, I see that chapter 3.2 talks about just these rules and many more emergent theorems.

Posted at 2:59 am | link