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mferraro89 commented on What is the inverse of a vector?   mattferraro.dev/posts/geo... · Posted by u/mkeeter
IshKebab · 4 years ago
I definitely agree but there's no way this is "English/American style". It's because people have grand plans of making their article/book accessible to everyone, and they start off explaining e.g. what a vector is, but pretty soon realise the don't want to write an entire vector algebra textbook so they seamlessly give up and jump straight into Stoke's theorem or whatever.

I read a Synopsys simulator manual that explained what double clicking was.

mferraro89 · 4 years ago
Did this article at some point give up and jump straight into something too difficult?
mferraro89 commented on What is the inverse of a vector?   mattferraro.dev/posts/geo... · Posted by u/mkeeter
deepsun · 4 years ago
English/American style of explanation fascinates me.

First, they show some algebra formulas and mention dot product and cross product. But then they start introducing a definition of a vector! With images!

Why, oh why do you need to waste yours and reader's time to introduce basic definitions, if any reader of the article definitely knows that? If they haven't, they wouldn't be able to read the first paragraph at all.

PS: Russian style of explanation is more like: "Here's the essence of my idea, maybe with some leading pre-definitions, but definitely without basics. If you are here, you probably is as curious as I am to already know/heard of all the basics." In total, there's more material, because it's easier to write and read it, as author didn't need to explain 101s to PhDs.

mferraro89 · 4 years ago
ha, thank you for your honest feedback. My intended audience is not PhDs or math majors, it is high school physics teachers, practicing engineers, programmers, precocious high school students, etc. Many of these people benefit from some definitions.

I include 3 sentences defining a scalar so that I could introduce the concept of grade.

I include a few sentences defining a vector because just read the comments here and you'll see there are many definitions of vector and I want to specifically call out the one I care about in this post. I am also using a nonstandard, color-based notation throughout the article so it is helpful to take a concept that people already know just to demonstrate my notation. This also lets me introduce the 3D interactive illustrations.

Did you read the rest of the article or were these two definitions so objectionable that you quit?

mferraro89 commented on What is the inverse of a vector?   mattferraro.dev/posts/geo... · Posted by u/mkeeter
foobarbazbarfoo · 4 years ago
love your writing, can anyone recommend blogs like these
mferraro89 · 4 years ago
thanks! the 3blue1brown website has some great written content that you may enjoy: https://www.3blue1brown.com/#lessons
mferraro89 commented on What is the inverse of a vector?   mattferraro.dev/posts/geo... · Posted by u/mkeeter
haunter · 4 years ago
Wow the interactive 3D illustrations are awesome. Works perfectly on touchscreen, feels very natural.
mferraro89 · 4 years ago
thank you! It took a whole month to get the 3D illustrations working well.
mferraro89 commented on What is the inverse of a vector?   mattferraro.dev/posts/geo... · Posted by u/mkeeter
jeffwass · 4 years ago
I stopped reading at this paragraph near the top :

“In this post we will re-invent a form of math that is far superior to the one you learned in school. The ideas herein are nothing short of revolutionary.”

mferraro89 · 4 years ago
why? too clickbaity?
mferraro89 commented on What is the inverse of a vector?   mattferraro.dev/posts/geo... · Posted by u/mkeeter
an1sotropy · 4 years ago
Yes, this. Though Zero to Geo is one of the links at the bottom of the article.

It is really a shame that article does not clarify that, btw, what we've just derived is a re-derivation of a thing that has already been expressed and named, by Clifford, and well-characterized: https://en.wikipedia.org/wiki/Geometric_algebra

Such a bummer to see very slick but very ahistorical articles.

mferraro89 · 4 years ago
Hi. I wrote whole section on the history of GA and what happened and why it isn't already the norm, but I chose to remove it because the article is already far too long, and I don't think that my intended audience (engineers, compsci people, university undergrads) would care about the history. Apologies that wasn't what you would have preferred.
mferraro89 commented on What is the inverse of a vector?   mattferraro.dev/posts/geo... · Posted by u/mkeeter
tgb · 4 years ago
You're right about that being wrong, and the author makes the same mistake consistently, but otherwise it looks correct. Some steps have details elided where it maybe should have been noted that things were being skipped, but with correct results. I think it's wonderfully written and a great exposition.
mferraro89 · 4 years ago
hey, if you have time to detail those mistakes I'd be happy to fix them in the text. Can you email me at mattferraro.dev@gmail.com
mferraro89 commented on What is the inverse of a vector?   mattferraro.dev/posts/geo... · Posted by u/mkeeter
codeflo · 4 years ago
The writing is cute and the animations are nice, but none of it makes any sense. I stopped reading at

> It is important to remember that bivectors have a certain redundancy built into them in the sense that s a ⃗ ∧ b ⃗ = a ⃗ ∧ s b ⃗ s a ∧ b = a ∧s b . We can write them using 6 numbers or 3 numbers, but they actually convey 5 degrees of freedom.

Three (real) numbers have three degrees of freedom, by definition. (And nothing about complex numbers was mentioned.) Is this a parody I don’t get? I feel like I have wasted ten minutes on nonsense.

mferraro89 · 4 years ago
author here. I was mistaken about the 5 degrees of freedom bit. Bivectors have three. I'll fix the text tonight. I'm sorry you wasted ten minutes on my nonsense.

u/mferraro89

KarmaCake day640January 19, 2021View Original