WEEKLY WHINE

The search continues

Due to the immense popularity of last week's Weekly Whine, we thought that we would answer the question that has been on everyone's minds: "But what if you search for partial derivatives with some other search engine?" This is of course a very valid question. So I went to Hotbot and searched for the phrase "partial derivative". I'm happy to report that none of the results linked to the same pages as did Altavista. However, there were some notable results from the search. Here, why don't you take a look.

It seems that in JUN 1995, one Dr Gawen R T Jenkin of the University of Edinburgh's Department of Geology and Geophysics posted this message, suggesting that researchers be more careful in their papers. There's a difference between a lowercase delta δ and a partial derivative symbol ∂. Dr Jenkin wants to ensure that people say what they mean and mean what they say. A noble pursuit, I would say.

This is another URL that contains the same file.

Yet another copy of the same message. How droll.

The MathGroup list contains people who have been using programs like Mathematica and other mathematical programs for hundreds of years. People send in their questions, and the MathGroup members send back their tips. This message is a response to someone who was having trouble evaluating a partial derivative. Don't click on Luci's address below her name; it will only confuse you. Unless, of course, you are Luci Ellis. If you are, it won't confuse you because you wrote it. Or maybe it will.

I guess JACAL is similar to Maple, Mathematica, and programs like that. This page is from the JACAL manual and explains the use of the partial command, which, surprisingly, evaluates a partial derivative of a given expression.

This is a page from the lecture notes of a calculus class at the University of Louisville. It explains that partial derivatives are found by fixing the other parameters and that partial derivatives don't mean continuity.

EXCALC is part of a program called REDUCE that also does mathematical jobs. This page is part of EXCALC's manual; it explains the use of EXCALC's partial differentiation operator, the at sign.

This was probably a homework set for students, but it is apparently not available. An attempt to collect this file gave me a 400 Bad Request message, telling me that the client should not repeat the request without modifications. Hey, who am I to argue?

This location will actually pass you from Wolfram Research's UK server to its US server. It shows the explanation of Mathematica's D symbol, which - in a shocking revelation - finds partial derivatives. It tries to evaluate them symbolically and only attempts a numerical solution if a symbolic solution is not possible.

This is an abstract of "Measurement of a Transparent Object by Using an Automated Talbot Interferometer", by Shigei et al. The paper was published in the DEC 1994 issue of Optical Review, Japan's only optics journal. The Optical Society of Japan has been publishing Optical Review since 1994; in fact, this paper was in the second issue. The abstract says that the authors found a way to measure the first partial derivative of a transparent object's phase distribution with a Talbot interferometer.