undefined | Better HN

0 pointssimiones4y ago0 comments

I would say that delta is typically used to mean difference of any magnitude (i.e. Δt could mean 2 hours).

0 comments

4 comments · 2 top-level

pbhjpbhj4y ago· 2 in thread

Yes, small changes usually use lowercase delta, e.g. δt. Not to be confused with the derivative symbol dt, nor with the partial derivative symbol ∂t !

Before I continued my maths learning after highschool (ie before UK A-levels) I learnt the Greek alphabet to make it easier to understand maths notations as I could 'voice' (internally) all the funny glyphs adopted from Greek.

At uni I learnt how to properly write an ampersand (for logic classes) and how to write Aleph and Beth (for pure maths, particularly transcendental numbers).

Some professors have a fondness for the more confusing Greek letters (lowercase xi, lowercase eta) ... is it n or eta, epsilon or xi, ...

wrycoder4y ago

https://en.wikipedia.org/wiki/Riemann_sum usually uses ∆. See also the explanation of ∆ at https://en.wikipedia.org/wiki/Derivative#Explanations .

That's the sense in which I'm using ∆, which is common, at least in the US.

Jensson4y ago

But this is a physics paper, that isn't how you use uppercase delta in physics. It is just a range. In physics however you do a ton of approximations all the time in ways mathematicians hate (you don't care about errors smaller than you can measure), so uppercase delta is often approximated with derivatives etc, but it isn't a derivative. Math in physics is way more practical and uses very different techniques than math in math, often because physicists invented the math first and mathematicians later went and formalized it.

wrycoder4y ago

True. To continue my example, the average velocity in the last hour would be taken with a ∆t of 60 minutes.

j / k navigate · click thread line to collapse