Wikipedia:Reference desk/Archives/Mathematics/2016 March 15

Welcome to the Wikipedia Mathematics Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

March 15

Pi day

Matt Parker's latest video [1] has him (somewhat misguidedly) attempting to calculate π by hand using the Leibniz formula for π. This led me to wonder, how close do various series acceleration techniques get when applied to this particular series stopping at the tenth term (1/19 — the last term used in the video)? For example averaging the last two partial sums gives you 2 digits accuracy which is an improvement over the 1 digit accuracy you get with raw partial sum, but Aitken's method gives 3 digits and Van Wijngaarden transformation gives about 5. Any others? I'd be particularly interested in seeing whether conformal mapping can be applied here; the article mentions this but doesn't give many details. --RDBury (talk) 00:47, 15 March 2016 (UTC)

Need help to learn Mathematics

Hello!, I do not know if this is the appropriate place to type my request, but I do not know about any other. I live in the province of Stockholm in Sweden, and wish to find a volunteer person who can teach me Mathematics (or Physics, but preferably Mathematics to start) at the university level. It can be in Spanish, English or Swedish. In return, I can perform some tasks, like house work, teaching Spanish and doing other things, because I am really interested in learning Mathematics, and I can not just watch videos or read books or internet pages (I have tried that for years, and got frustrated). So, if anyone is willing to help me (or knows about someone who can and wishes), please let me know (email address redacted). Thank you very much.213.113.87.132 (talk) 12:44, 15 March 2016 (UTC)

I have another suggestion for you. Select a couple of Wikipedia math articles at a level you barely understand. Try to improve those articles, and make sure you understand to 100% the edits you make (so that they are actual improvements). YohanN7 (talk) 13:38, 15 March 2016 (UTC)

I don't agree. Wikipedia technical articles tend to be written by, and for, people who already know the material. So, a mathematics article written for mathematicians is of just about no use to the general public. For an example of how it should be done, see weighted arithmetic mean, which starts out with simple to understand examples before getting into the heavy math terminology. StuRat (talk) 17:06, 15 March 2016 (UTC)

You probably don't understand what I mean. I personally don't contribute much to math (or physics) articles I understand. Waste of my time, and boring. But I do write articles/make total rewrites on topics I don't understand but wish to understand, and come out understanding the topic better than most because I put myself in a position where I need to write an encyclopedic text about it that will sooner or later be scrutinized by experts. So far, few complaints from the math/phys community. This works for me, and I think others should try. Granted, there are those that think experts only should be editing mathematics/physics. "Quasars become laser stars" I respect that position, but I don't care to respect it enough to follow suit. YohanN7 (talk) 09:02, 16 March 2016 (UTC)

There are services that can help match you with someone who wants to trade. One I know of is called Skillshare here [2]. I do not know if there's a general name for this type of service, but it's basically barter for training services. SemanticMantis (talk) 15:27, 15 March 2016 (UTC)

You might consider browsing the Stockholm University https://sisu.it.su.se/

University studies are free in Sweden. You may consider a preparatory internet course they have to start off with. https://sisu.it.su.se/search/info/MM1003 Since it is an internet course, chances are that anyone at all may be eligible. If not, Coursera have maths courses from many universities around the globe. I think they are all free. As for university credits, the course I linked to at the university of Stockholm gives credits. A few Coursera courses give credits. Star Lord - 星爵 (talk) 20:25, 15 March 2016 (UTC)

Can you tell us why you want to learn mathematics? Motivation is very important, nothing is worse than forcing yourself to learn something which you find uninteresting. Is there a problem which you want to solve but you lack the mathemtical tools to do so? 175.45.116.66 (talk) 22:01, 15 March 2016 (UTC)

Thank you all for your answers. I would like to read something useful, but I appreciate your time to make those suggestions. Now I am going to explain my situation a little more, because with a better understanding of something, we can make better comments, right?.

I love Wikipedia (and think that everybody does), and would like to help in any manner, but let us be realistic: I have never written a single article in my whole life, and with my only knowledge of high school mathematics (up to pre-calculus level), I definitely do not think that I could contribute to it (I could translate from English to Spanish or Spanish to English if it is needed, but how could that teach me mathematics? [anyway, please let me know if I can help in a realistic way]).

I have been at www.skilllshare.com, and it is a paid site, besides, they do not teach mathematics there, and they teach their topics online (I am not looking for online courses, as I do not feel any motivation for studying online or alone [which are about the same]).

Of course anybody with a normal understanding interested in learning mathematics and living in Sweden would have thought about the University of Stockholm (that is something very obvious). University studies are not free in Sweden (at least not for non-European people), that is a false assumption. Besides, almost no university in the world would gladly accept a 45 year-old person with his/her hair almost totally white as a first year student (I hope you understand what I mean by "first year"). Some other reasons for not applying at a university (besides the age) are: lacking of documentation to live in the country, money (I am unemployed, so I have all the time to study but no money), I do not think I would pass admission tests (I got frustrated [and perhaps traumatized] with those SAT tests they have in the United States, because when living there, I applied to Harvard University in 2,004 [they accept less than 10% of applicants from the whole world, and the results of my tests were not high enough]). I am not looking for credits or certificates, as they would have not use at this point in my life, I just want to pursue the biggest passion of my life, which is mathematics (and hope not to leave this world without learning some).

For many (more than 20) years I have tried to learn by myself, and I have more than enough material (everything recorded in a hard disk), but I loose motivation very easily when studying by myself (we live in a society, human beings were not created to live alone), and have not gotten any further than pre-calculus (then, how could I learn differential equations, for example?), so I recognize that I need someone to teach me (or at least to belong to a study group, but not online).

For those reasons and some others, I think that the only solution to my case, would be to have a person who can teach me personally, I know that I am really good at mathematics, but lack of motivation has been one of the biggest problems in my life, that is one of the main reasons why I can not learn much alone.

I hope that you understand my situation, and appreciate your time for answering and for reading such a long story. Again, thank you very much.213.113.87.132 (talk) 00:35, 16 March 2016 (UTC)

Since you are hoping for something in-person, it seems to me that you would be better served by some website that has a geographic focus; even Craigslist Stockholm (I do not know if it exists, but something similar) would be more likely to work, I would think. (Sorry, I know this is not very constructive.) --JBL (talk) 02:12, 16 March 2016 (UTC)

    Thank you for the suggestion.  I have been constantly at http://stockholm.craigslist.se, but have not found anything useful (will keep looking there, though).  The advertisements there are mainly for buying and selling, finding apartment or house, finding jobs (the usual things) and for people looking for a relationship (well, I guess I could do about the same as the famous Russian mathematician Sofia Kovalevskaya did).  And before anyone suggests it, I have already been to www.blocket.se.

    I thought that because the Nordic countries are some of the most developed in information technologies in the world, that some Swedes would read this post.  Well, does anyone know about a website where I can get the help that I need?.  Thank you very much.213.113.87.132 (talk) 17:00, 20 March 2016 (UTC)

Suggestion for redirect/stub?

Hi, I'd like to un-redlink arbitrary constant. We have constant and mathematical constant and things like constant of integration. I believe this certainly deserves at least a re-direct and possibly needs a stub article. Can you either suggest a redirect target article/section or convince me that it needs a stub to be handled properly? Here is a smattering of links to people asking questions arbitrary constants ([3] [4] [5] relation to parameters, variables, non-arbitrary constants etc.) It would be nice if we had some content on the matter. SemanticMantis (talk) 15:25, 15 March 2016 (UTC)

Certainly you'll see "let this and that be arbitrary but fixed" in the literature. But "arbitrary constant" is rare to see. Maybe a stub on how these concepts should be interpreted, with enough redirects to cover variations. YohanN7 (talk) 15:34, 15 March 2016 (UTC)

Additional context: This google ngram [6] shows that "arbitrary constant" has very similar frequency to "constant of integration" and is much more used than "arbitrary but fixed". Here [7] is a brief entry for arbitrary constant in a dictionary of mathetmatics.SemanticMantis (talk) 15:49, 15 March 2016 (UTC)

I don't think of "arbitrary constant" as a technical term worthy of an article or even a redirect. I think of constant (mathematics) as a technical term, and I think of "arbitrary" as simply a common English adjective. If you do feel the need for a redirect, I would redirect it to constant (mathematics). Loraof (talk) 17:19, 15 March 2016 (UTC)

Thanks. I too wondered about this perspective for a bit. I eventually realized that that argument also applies essentially verbatim to constant of integration and many other math article. I don't think we should delete the article on constants of integration, even though the term can be understood via English grammar, constant, integration and a bold belief in compositional semantics :) SemanticMantis (talk) 18:20, 15 March 2016 (UTC)

But in "constant of integration", every word except of is technical. In "arbitrary constant", on the other hand, the only word that is technical already has its own page. Loraof (talk) 21:17, 15 March 2016 (UTC)

The phrase "constant of integration" contains more information than "a constant that relates to integration." The phrase "arbitrary constant" does not contain more information than "a constant whose value is arbitrary." --JBL (talk) 15:31, 16 March 2016 (UTC)

I agree to a point but that's no reason why we can't have a redirect or stub. The very fact that people ask questions about arbitrary constants vs. parameters and variables means that having WP coverage would be valuable. SemanticMantis (talk) 14:55, 17 March 2016 (UTC)

As far as I can find, there is nothing to 'un-redlink' here. The only place with links to arbitrary constant is a Reference Desk; see Special:WhatLinksHere/Arbitrary_constant. And the only use as an actual reference to the article is in Semantic Mantis' statement at WP:RD/L (in which, IMVHO, Mantis should define the lacking term). --CiaPan (talk) 12:08, 16 March 2016 (UTC)

Well, I linked it there because I thought it was appropriate, and I was mildly surprised that no redirect or stub existed. Do you all really not recall seeing this term in many textbooks? Have you never heard a student express confusion over what the term means? I have demonstrated both fairly frequent use and evidence of confusion, so I don't think I'm making a weird call on my claim that a stub or redirect would be useful. If you disagree, that's fine, I'll just do as I see fit. SemanticMantis (talk) 15:13, 16 March 2016 (UTC)