# Talk:Abraham de Moivre

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## Pronunciation of name

My university maths lecturers claimed one should pronounce his surname DE MOY-VER (i.e. in an english-phonetic way), saying that upon his exile to England he insisted people did so, as he was now thouroughly english and not in the least frenchy. If anyone else has heard this, then I think it should go into the article (but it smacks just a bit of the kind of nonsense maths lecturers come up with in order to break the tedium, so I'm not putting it in myself). -- Finlay McWalter | Talk 19:54, 1 Apr 2004 (UTC)

thank you for writing the pronunsiation note!

You can hear two pronunciations here.

## Fibonacci Numbers

There is some believe that he discovered a method of finding the n-th Fibonacci number before Binet or Euler did. deMoivre vs Binet

See de Moivere's Miscellanea Analytica (London: 1730), p 26-42. for his solution to general linear recurrences deriving an expression linking Φ to the nth power to the nth Fibonacci number. See The Art of Computer Programming, Second Edition, 1973, p 82, by Donald E. Knuth.

## WikiProject class rating

This article was automatically assessed because at least one article was rated and this bot brought all the other ratings up to at least that level. BetacommandBot 02:05, 27 August 2007 (

De Moivre was a good friend of Isaac Newton. He calculated when he would die. He slept fifteen minutes longer each day, and said that the day he slept 24 hours he would die, and his prediction was correct.

Too long day On April 21, 2009, the information about how he had calculated the day when he would die was changed into "1.5 minutes per day" plus the info that he did it when he was 42. As he died when he was 87, this would give 1.5 * ((87-42) * 365 + 12)/60 = 410.925 hours in a 24-hour day. I added 12 for leap years, but even without it it would be definitely too much. So when did he exactly predict it and how many minutes per day was it? Could anybody help correct it please? --C. Trifle (talk) 16:00, 27 April 2009 (UTC)

## Citation for deMoivres formula

I've put a citation needed on the original thing deMoivre was supposed to have proven:

$\cos x = \frac{1}{2} (\cos(nx) + i\sin(nx))^{1/n} + \frac{1}{2}(\cos(nx) - i\sin(nx))^{1/n}$

because it is only one pair of the roots for which this is true. Dmcq (talk) 17:24, 9 December 2009 (UTC)

Agreed, but different reason. I have a German text from 1903 that explains de Moivre's works. It makes specific reference to
$\cos x = \frac{1}{2} (\cos(nx) + i\sin(nx))^{1/n} + \frac{1}{2}(\cos(nx) - i\sin(nx))^{1/n}$
but, it says that this is how we (mathematicians of the 1900s) would write this. I've only seen de Moivre's original Miscellanea analytica, and the symbols of sin, cos, and i are not used despite that the solution methods are using trigonometric techniques. Instead, de Moivre uses variables to represent things like the "ratio of the arc". Most explanations of trigonometric properties are verbal, rather than sybolically noted.
But there is a problem, as Dmcq notes in this change. The author of the German text explains that DeMoivre was interested in the two equations
$y = \frac{1}{2}\sqrt[n]{\sqrt{1+a^2}+a} - \frac{1}{2}\sqrt[n]{\sqrt{1+a^2}-a}$
$y = \frac{1}{2}\sqrt[n]{a + \sqrt{a^2 -1}} + \frac{1}{2}\sqrt[n]{a - \sqrt{a^2 -1}}$
These equations were derived from a certain polynomial series where n is an odd integer. A citation shows that de Moivre knew that there were 5 roots when n=5 and works out such a problem, but it appears he was only interested in finding the real root in the solution process. Take note also that in these equations $y = \sin{\phi}$ and $a = \sin{n \phi}$. I think the problem may be in giving context.
A copy of the German text is available freely on Google, but I don't know of an English translation: https://play.google.com/store/books/details/Anton_Braunm%C3%BChl_Edler_von_Vorlesungen_%C3%BCber_Geschic?id=uB0PAAAAIAAJ#?t=W251bGwsMSwyLDUwMSwiYm9vay11QjBQQUFBQUlBQUoiXQ..

Thelema418 (talk) 00:06, 21 August 2012 (UTC)

## Death Prediction

Can anyone find an accurate source for his prediction of death? —Preceding unsigned comment added by Hmyt (talkcontribs) 19:56, 31 January 2010 (UTC)

## amateur mathematician

for some reason Wikipedia lists Abraham de Moivre on the "List of amateur mathematicians." The description is "people whose primary vocation did not involve mathematics (or any similar discipline) yet made notable, and sometimes important, contributions to the field of mathematics." After reading this page, I would debate de Moivre's inclusion on this list; he certainly seemed to be involved with mathematics as his primary vocation. Owen214 (talk) 06:59, 8 August 2011 (UTC)

## Probability

The attribution of the normal distribution to de Moivre is not quite correct. I think this needs expanding upon. De Moivre found a large sample approximation to binomial probabilities in terms of what we now know as a normal distribution. However, he was only interested in discrete distributions and did not think of his formula as a probability distribution in its own right. For this reason he is not usually credited with the discovery of the normal distribution.TerryM--re (talk) 04:30, 9 March 2014 (UTC)