Talk:Logarithm/GA2

GA Review

Article (edit | visual edit | history) · Article talk (edit | history) · Watch

Reviewer: Racepacket (talk) 03:28, 17 January 2011 (UTC)

Please fix disamb link: Random number and Shell. No bad links.

Done. Jakob.scholbach (talk) 22:35, 17 January 2011 (UTC)

GA review (see here for criteria)

1. It is reasonably well written.

   a (prose): b (MoS for lead, layout, word choice, fiction, and lists):

   Please consider whether the lead can be improved? Would a math novice get by with just reading the lead and skipping the rest of the article?

   This has been subject to repeated attention (most recently by Lfstevens), but I'll revisit it! Any particular suggestions/concerns? Jakob.scholbach (talk) 22:32, 17 January 2011 (UTC)

   I tweaked it a little bit. We do have things like complex number, inverse function, fractals, which will be difficult to comprehend for, say, a 15y old. However, I feel that the points which are elementary are described in an elementary way. Areas which are accessible only with more mathematical (or other, say for forensic accounting) background or curiosity are presented in a manner that does not try to dumb it down. All in all I think this is a reasonably self-contained lead section. Do you agree? (If not, what could be done better?) Jakob.scholbach (talk) 22:48, 18 January 2011 (UTC)

   "Write the logarithm of x to the base b as logb(x), such as log10(1000) = 3, using parentheses for clarity." - avoid imparative mode. How about, "People write..." Are the parentheses for "clarity" or a result of generalized function notation?

   Done (and removed the parenthesis point). Jakob.scholbach (talk) 22:32, 17 January 2011 (UTC)

   "They describe musical intervals, inform" - do you mean logarithms or logarithmic scales?

   Good catch. Now rearranged. Jakob.scholbach (talk) 22:32, 17 January 2011 (UTC)

   I suggest that you use a method other than {{cref}} The notation is not widely-used and is so small it is hard to read. use group ref feature instead - it designates in numerical or alphabetical order.

   Done. Jakob.scholbach (talk) 22:27, 18 January 2011 (UTC)

   "Derivatives and antiderivatives of logarithms to other bases can be derived therefrom using the formula for change of bases." -> "Derivatives and antiderivatives of logarithms to other bases can be derived from this equation using the formula for change of bases."

   Good idea. Jakob.scholbach (talk) 22:32, 17 January 2011 (UTC)

   "or transcendental.[12]"->"or a transcendental number.[12]" - parallel sentence construction.

   OK. Jakob.scholbach (talk) 22:32, 17 January 2011 (UTC)

   "putting A = z/exp(y),"- would this be more readable (and more consistent with the next equation) using <math>A = \frac(z)(exp(y))</math>, instead of an inline fraction?

   OK. Jakob.scholbach (talk) 22:32, 17 January 2011 (UTC)

   Please rephrase: "Logarithms are used in the process of maximum likelihood estimation when applied to a sample consisting of independent random variables: maximizing the product of the random variables is equivalent to maximizing the logarithm of the product, differentiating a sum rather than a product." - the word diffentiating has multiple meanings.

   Done (removed the "differentiation"). Jakob.scholbach (talk) 22:32, 17 January 2011 (UTC)

   Please elaborate that a slide rule is based on its scales being marked in logarithmic distances.

   Done. (Along with the reorganization of the pictures). Jakob.scholbach (talk) 22:49, 18 January 2011 (UTC)

   "Mathematically unsophisticated individuals"->"Psychological experments find that mathematically unsophisticated individuals"

   I don't have strong feelings about this, but why do you want this reword? Your suggested addition makes it slightly longer and does not seem to convey much more information (IMO)? The other reason, taking a more distant point of view than by merely stating this fact, also seems not to be necessary here. Jakob.scholbach (talk) 22:32, 17 January 2011 (UTC)

   How about "Studies show that math..." I am worried that you are popping off an interesting fact without relating it to the world of psychological research. The reader will ask how do you know this and why is this sentence here?

   OK, that's a fair point. Now reworded. Jakob.scholbach (talk) 22:27, 18 January 2011 (UTC)

   "The logarithm of a log-normal distribution is normally distributed.[36]" - can you give a real world example of a log-normal distribution so that we can avoid a one sentence paragraph?

   OK, I gave an interesting one (even though I feel kind of incompetent to judge what example is most relevant.) Jakob.scholbach (talk) 22:27, 18 January 2011 (UTC)

2. It is factually accurate and verifiable.

   a (references): b (citations to reliable sources): c (OR):

3. It is broad in its coverage.

   a (major aspects): b (focused):

   In history section, how about adding the use in computing the Ballistic Trajectory tables of artillery shells in World War I. (In World War II, they used the first digital computers to compute the tables.)

   I'm not in principle against, but none of the sources I saw mentioned this particular application. Therefore I did not (and still would not) include it here. Jakob.scholbach (talk) 22:32, 17 January 2011 (UTC)

   Ordinance computations was a big computational consumer and financed the first computer. See: [1] and Computers: A Life Story of a Technology.

   I don't doubt at all that ballistic computations motivated building computers. But I fail to see how this is related to logarithms. Do you know this? The links you provide don't seem to back up that close a relation. (The first doesn't seem to mention log's at all, the second mentions the relation of logarithms to the slide rule (which we do cover) but the few pages I can see in google don't seem to talk about ballistic curves)? If you can provide a specific source that talks about the connection of log's (or log tables, as opposed to other mathematical tables) and ballistic curves I'm open to include it here, but right now I think they are not closely related or unrelated. Jakob.scholbach (talk) 22:27, 18 January 2011 (UTC)

   Why do you include an example of an equation for a straight line of a semi-log graph paper, but did not include an example of a straight line for log-log graph paper?

   Again, I'm open to discussion here. I did not include it because the (few) sources dealing with log graphs mostly focus on log-linear graphs, less so on log-log graphs. Maybe because the former reduce the large-scaled exponential functions (as opposed to polynomials) to straight lines? Whatever the reason is, I think this article should for balance reasons only contain one of the two possible pictures, and I think the log-linear is more important and also easier to understand. Jakob.scholbach (talk) 22:32, 17 January 2011 (UTC)

   Without actually displaying the log-log graph, couldn't you give an example (either as an equation or as a real world application) where someone would want to draw a log-log graph and would expect a straight line.

   I briefly explained how they work and linked to power laws. Any more than this should go, I believe, to the (quite stubby!) sub-article. Jakob.scholbach (talk) 22:27, 18 January 2011 (UTC)

   When I was in 9th grade, we were trained to use both a slide rule and also logarithm tables. In order to use log tables we were introduced to the concepts of characteristic and mantissa. These concepts later helped me understand scientific notation and computer internal representations of floating point numbers. (Now called exponent and significand.) While I agree that "characteristic" and "mantissa" have no theoretical significance, an argument can be made that they should be mentioned in the article. Otherwise, readers may wonder why the C/D scale on your photo of the slide rule only goes from 1 to 10 or how a log table could fit in the back of a math textbook.

   I provided a brief explanation of these notions next to the log tables. Jakob.scholbach (talk) 21:38, 19 January 2011 (UTC)

   Please consider using the image File:Slide rule example2.svg in addition to the photo.

   Thanks for this. I think I will create a tiny variant of this file showing a particular point highlighted and replace the photo by this svg file. However, this might take a few days. Jakob.scholbach (talk) 22:32, 17 January 2011 (UTC)

   Please keep the photo of the slide rule, perhaps at a thumbnail size. Before you create more illustrations, look at what is being used in the article Slide rule and Common logarithm.

   I did replace the photograph. I hope this is OK with you? Here is why: the photo was of course more realistic, but hard to see what is going on because it is quite small (even at the size we had it). We do not (and cannot, for space reasons) discuss the whole functionality of the slide rule in this article, so matching the most basic information with an likewise basic picture seems beneficial to me. So I prefer the illustration over the photo. I think, for space reasons, we cannot afford two pictures of the s.r. here (actually the previous GA reviewer criticized the article for having too many pictures...). Jakob.scholbach (talk) 22:27, 18 January 2011 (UTC)

   How about discussing "Napier's bones?"

   Undoubtedly a good invention, but how are they related to logarithms? (Other than having the same creator, of course.) For whatever this is worth, Napier's bones points out that they are different.Jakob.scholbach (talk) 22:27, 18 January 2011 (UTC)

   My mistake.Racepacket (talk) 10:45, 19 January 2011 (UTC)

4. It follows the neutral point of view policy.

   Fair representation without bias:

5. It is stable.

   No edit wars, etc.:

6. It is illustrated by images, where possible and appropriate.

   a (images are tagged and non-free images have fair use rationales): b (appropriate use with suitable captions):

   Thank you for contributing the graphs and charts.

7. Overall:

   Pass/Fail:

   I am placing the article on hold. Racepacket (talk) 05:36, 17 January 2011 (UTC)

Please don't overlook the comment in red. Racepacket (talk) 11:09, 19 January 2011 (UTC)

1. Now dealt with (hopefully).

Thanks, Racepacket, for your review! I think all points you raised are now covered. Jakob.scholbach (talk) 21:38, 19 January 2011 (UTC)

Congratulations. Well done. I have corrected the log table discussion, rather than do another round of comments. I hope that you agree. Racepacket (talk) 03:15, 20 January 2011 (UTC)

Kudos to the editors of this now-excellent piece. Way to go! Lfstevens (talk) 00:33, 1 February 2011 (UTC)