# Tag Info

Accepted

### Who did first use the Method of Characteristics?

[EDIT: check the (*) for a potential earlier reference in Lagrange] The first mathematician (who used the methods of characteristics for differential equations) seems to be Paul Charpit de Villecourt ...
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### History of hypergeometric equation

If $a=b=c=0$ we get a first order separable equation for $y'$, viz. $\ x[(1-x)y''-y']=0$ whose solution $y'= c(1-x)^{-1}$ would have been obvious since at least Bernoulli. Dutka (1984, p. 16): In ...
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### What is the origin of the term "Ordinary Differential Equation"?

The name "Ordinary Differential Equation", together with an explanation of why the term "ordinary" is used, is found in 1828 in An Elementary Treatise on the Differential and Integral Calculus by ...
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### source of "logistic growth"?

According to some on-line resources for historical French lexicon, around 1770 [see : Fortunato Bartolomeo De Felice, vol.26 of: Encyclopédie ou Dictionnaire universel raisonné des connoissances ...
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### Source of claim that Leibniz discovered separation of variables for ODEs in 1691?

The reference is probably to a treatise sent to Huygens on 5 October 1691, where Leibniz says (and illustrates with several examples) that "Whenever the subtangent [$=y/y'$, but it would also work for ...
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### Does the “O” in the google doodle for Olga Ladyzhenskaya have anything to do with her work?

The equation in the picture is the Navier–Stokes momentum equation in convective form. The part inside the O looks like a cross-section of (the velocity field of) a flow between two rotating ...
• 78k
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### What is the etymology of "phase space" of a dynamical system?

Here is a direct link to Nolte's Tangled Tale of Phase Space on Physics Today. Big takeaways: the name did not come from Liouville's oft-cited 1838 paper, and Boltzmann used "phase" without &...
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### How did Peano prove his existence theorem without Ascoli's theorem?

Peano did do something else, and not quite right, apparently. In 1969 Kennedy published a note in the American Mathematical Monthly titled Is There an Elementary Proof of Peano's Existence Theorem, ...
• 78k
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### History behind the heat equation

Heat equation was first formulated by Fourier in a manuscript presented to Institut de France in 1807, followed by his book Theorie de la Propagation de la Chaleur dans les Solides the same year, see ...
• 78k
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### What is the origin of the "Japanese bracket"?

I can provide a partial response to this question. As noted in my earlier comment, the term "Japanese bracket" appears in the 1999 paper "Global existence of small solutions to the ...
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### History of hypergeometric equation

1) For $a=b=c=0$ we have equation $$x(1-x) \dfrac {d^2y}{dx^2}-x\dfrac {dy}{dx}=0$$ with solution $C_1 + C_2\log(1-x)$. This would probably not be considered hypergeometric, except in a degenerate ...
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