Jumping on the bandwagon to say

Video is asking "why did people come up with Algebra, what did they even use it for?" The tweeter mocks her and says "the technology we have now is because of ages of algebra evolution"

Notice this doesn't answer the question! https://twitter.com/aIeturner/status/1298372968838508546

Sure, you might use algebra to model gravitational forces... but our algebra is way older than our knowledge of gravity. So they _couldn't_ have invented it for that purpose. This isn't a question about "how is math useful", it's "how WAS math useful".

Especially when you consider that the math we have now is VERY different from the math the Greeks had! You know how we use x,y,z to represent variables? That's from 1637. https://en.wikipedia.org/wiki/La_G%C3%A9om%C3%A9trie The first known use of variables *at all* is from 628, a millennium after Pythagoras.

(Ref for above: https://en.wikipedia.org/wiki/Br%C4%81hmasphu%E1%B9%ADasiddh%C4%81nta)

That's actually pretty cool. It shows how we can improve our understanding of math, and apply it more broadly, by figuring out better *notations* for it, better ways to describe what we're doing.

So what originally motivated the study of Geometry and Algebra?

¯\\_(ツ)_/¯

No seriously, I don't know. I know a lot of math, more than most layfolk know, but there's a big difference between knowing math and knowing the history of math. Which is its own rich field.

Unfortunately a lot of that richness is hidden from the public, since we're taught math in its current form, not what motivated the math in the first place. Part of this is that the motivating problems are often too messy to be good pedagogy, but it's pretty unfortunate.

The first dedicated book on algebra, Al-jabr (الجبر), seems to have been at least partially motivated by calculating inheritance rules and reconciling lunar and solar calendars, which are 1) really cool problems, and 2) require a lot of domain knowledge

https://en.wikipedia.org/wiki/The_Compendious_Book_on_Calculation_by_Completion_and_Balancing

If I was forced, *right now*, to make a guess on the origins of geometry and algebra without getting a chance to do research, I'd GUESS that they were heavily motivated by surveying. How much land does Pausanias own → how much tax does Pausanias pay

Other good candidates would be commerce and army logistics, but I'm less confident about the latter. Or I could spend ten minutes looking it up, but lol I'm too lazy for that.

tl;dr don't make fun of "stupid questions" if you can't answer them yourself, or ever, really

Update, I did two minutes of research and a lot of early geometry was actually motivated by architecture! If you need to build a circular structure with a diameter of N, how much material will you need for the walls? Bam, suddenly pi.