Timeline for $\frac{dy}{dx}$ versus $\frac{{\mathrm d}y}{{\mathrm d}x}$
Current License: CC BY-SA 3.0
8 events
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| Mar 1, 2018 at 8:40 | comment | added | Michael Bächtold | @Conifold Your comment is formulated slightly misleading then. Also, probably you meant to say "differential of x" was the infinitesimal increment, not "differential" was the increment. You wouldn't say "sine is a number" but "sine of x is a number". | |
| Mar 1, 2018 at 8:27 | comment | added | Conifold | @MichaelBächtold "it" in the comment refers to $dx$, not $d$, "differential" was the infinitesimal increment, and Leibniz used $\omega$, $l$ and $x/d$ for it before settling on $dx$. | |
| Mar 1, 2018 at 8:12 | comment | added | Michael Bächtold | @Conifold do you have a reference of where Leibniz interprets d by itself as a length? (As opposed to interpreting dx as a length.) Also I assume that the reading of $dx$ as "the differential of $x$" is quite old, or even starts with Leibniz? | |
| Nov 25, 2017 at 4:15 | comment | added | Conifold | The idea that d in d$x$ represents a differential operator is rather ahistorical. The notation predates such interpretations by about 200 years, for Leibniz it represented an infinitesimal length. Even Cartan, who invented the differential as an operator and $dx$ as a 1-form, still wrote it $dx$. | |
| Nov 22, 2017 at 14:15 | comment | added | Michael E2 | @DaveLRenfro Yes, thanks. It seems to be a thing with that author: 1962, 1964, 1965. Surprising, if he did it on his own, but someone started it, I suppose. | |
| Nov 22, 2017 at 12:48 | comment | added | Dave L Renfro | FYI, the earliest appearance of this notation I know of is the 1966 book Calculus of Residues by Dragoslav S. Mitrinovic. However, this issue is not something that I've been keeping track of, so this reference may be a weak lower bound. I only remember this reference because a few months ago I made some notes from a library copy of this book, and my notes include the fact that the notation d$x$ is used in integrals, which I thought was interesting for a 1966 book. | |
| Nov 22, 2017 at 9:49 | vote | accept | JRN | ||
| Nov 22, 2017 at 1:46 | history | answered | Michael E2 | CC BY-SA 3.0 |