Threadwell

Recent Notes

  • DemetriSpanos

    Oct 06, 2026

    • archive
    • twitter
    • demetrispanos
  • NOTimothyLottes

    Oct 06, 2026

    • archive
    • twitter
    • notimothylottes
  • bonzajplc

    Oct 06, 2026

    • archive
    • twitter
    • bonzajplc
Home

❯

Archive

❯

Threads

❯

EricLengyel

❯

How many people were taught that the formulas for the dot product (x₁x₂ + y₁y₂ + z₁z₂) and cross product (y₁z₂ − y₂z₁, z₁x₂ − z₂x₁, x₁y₂ − x₂y₁) are simply definitions and cannot be derived?

❯

@EricLengyel Unfortunately, I was.

@EricLengyel Unfortunately, I was.

Properties5
typearchive
sourcetwitter
date2020-02-17
tagsarchive, twitter, ericlengyel
description@EricLengyel Unfortunately, I was.

Feb 17, 20201 min read

  • archive
  • twitter
  • ericlengyel

Source

  • URL: https://x.com/pikuma/status/1229232718061473793
  • Author: pikuma.com (@pikuma)
  • Posted: 2020-02-17 02:34:52

Branch

1/ @pikuma

@EricLengyel

Unfortunately, I was. I had to go out of my way to find a satisfying answer to this… years later.

Related

  • Spine: 2020-02-17-how-many-people-were-taught-that-the-formulas-for

Graph View

  • Source
  • Branch
  • Related

Backlinks

  • How many people were taught that the formulas for the dot product (x₁x₂ + y₁y₂ + z₁z₂) and cross product (y₁z₂ − y₂z₁, z₁x₂ − z₂x₁, x₁y₂ − x₂y₁) are simply definitions and cannot be derived?

Created with Quartz v5.0.0 © 2026

  • GitHub