tel
Reputation
288
Top tag
Next privilege 500 Rep.
Access review queues
 Dec18 awarded Curious Dec17 awarded Commentator Dec17 comment Construct a midpoint of two parallel lines with only straightedge @WillJagy assume a normal pencil. Also a standard electric drill Dec17 comment Construct a midpoint of two parallel lines with only straightedge @WillJagy I actually just need to drill some holes in it, but I figured "cut in half" sounded more parabolic Dec17 comment Construct a midpoint of two parallel lines with only straightedge Ha ha, I was sort of hoping there was a better answer than that. My straightedge is too short! Dec17 asked Construct a midpoint of two parallel lines with only straightedge Dec6 awarded Good Question Sep24 awarded Autobiographer Apr12 comment When are $\Delta x$, $\delta x$, $dx$, and $\text{đ}x$ exactly the same? When are they approximately the same? @Rustyn if you could explain why they can't be legitimately substituted for one another, that would possibly be the best thing of all. I asked this question on the math SE instead of the physics SE on purpose. What I'd really like is some kind of exact comparison of the meaning of these various symbols to use as a guide for understanding these types of substitutions in the physics literature. Apr12 comment When are $\Delta x$, $\delta x$, $dx$, and $\text{đ}x$ exactly the same? When are they approximately the same? @achillehui thanks, that makes it clearer. What I'd really like to know though is when can one be legitimately substituted for another Apr12 revised When are $\Delta x$, $\delta x$, $dx$, and $\text{đ}x$ exactly the same? When are they approximately the same? added stuff about inexact differential $\text{đ}x$ Apr12 comment When are $\Delta x$, $\delta x$, $dx$, and $\text{đ}x$ exactly the same? When are they approximately the same? @crf all I know for sure about $\delta x$ is "something something calculus of variations, waves-hands" Apr12 comment When are $\Delta x$, $\delta x$, $dx$, and $\text{đ}x$ exactly the same? When are they approximately the same? @crf no. Here's an example of how $\delta x$ is used in the first chapter of Kardar's Statistical Physics of Particles: $\delta E \leq T\delta S + \bf{J}\cdot \delta \bf{x}$ Apr12 asked When are $\Delta x$, $\delta x$, $dx$, and $\text{đ}x$ exactly the same? When are they approximately the same? Aug8 awarded Notable Question Jul31 awarded Yearling Jun23 awarded Popular Question Apr19 accepted If $\log_{b}N$ is rational, what are the limitations on the possible values of $b$ and $N$? Apr17 comment If $\log_{b}N$ is rational, what are the limitations on the possible values of $b$ and $N$? That's what I thought, but I wasn't sure if it was necessary. I don't suppose you could humor me with a proof of the necessity? Apr17 asked If $\log_{b}N$ is rational, what are the limitations on the possible values of $b$ and $N$?