Imaginary Numbers Are Real [Part 1: Introduction]
Why Hacker News recommends it
HN commenters rate the series as some of the best visual teaching on complex numbers and recommend it for building intuition.
What it is
The first part of Welch Labs' series on imaginary numbers, presenting them as the natural extension of the number line into two dimensions. It covers the history and the math with strong visuals.
Recommended by 7 HN commenters across 7 different months, 2017 to 2025.
What Hacker News said
Strong rec pedrodelfino · 2017-08 · on “Imaginary Numbers Are Real – YouTube Series”
The greatest audiovisual content on the topic I have ever seen: Part 1 - [this video] Part 2 - [LINK] Part 3 - [LINK] Part 4 - [LINK] Part 5 - [LINK] Part 6 - [LINK] Part 7 - [LINK] Part 8 - [LINK] Part 9 - [LINK] Part 10 - [LINK] Part 11 - [LINK] Part 12 - [LINK] Part 13 - [LINK]
Strong rec rrauenza · 2017-12 · on “What are the complex numbers, really?”
Welch Labs has a wonderful series on youtube on imaginary numbers, "Imaginary Numbers Are Real": [this video] I like to tell my kids that imaginary numbers aren't really imaginary .. that in many ways they're more real than the Reals.
Strong rec wodenokoto · 2021-09 · on “A layman’s guide to recreational mathematics videos”
Welch labs has an amazing series on complex numbers called “imaginary numbers are real”. Great explanations, engaging content and high production value. [this video]
Strong rec tails4e · 2022-10 · on “The paper that keeps showing up”
Yes, the name imaginary does it no favours. I was confused for so long about i, as it was never explained on classes, and it wasn't until 3blue1brown and other math youtubers showed me the light. I really like this series on it by Welch Labs - loads of easily digestible videos, and a history lesson to boot: [this video]
Recommends jatsign · 2018-08 · on “A Visual, Intuitive Guide to Imaginary Numbers (2007)”
I really enjoyed this video series on imaginary numbers. Went through the history as well as the math: [this video]
Recommends magnetomax · 2023-02 · on “Ask HN: What's the best lecture series you've ever seen?”
Regarding imaginary numbers, I found this YouTube series really helpful to understand basics of imaginary numbers. [this video]
Recommends wanderingmoose · 2025-01 · on “Quaternions and spherical trigonometry”
I really like the welch labs series on imaginary numbers which covers the first part of what you talk about -- leveling up the notion of what a complex number is. Though his focus was more on solving simple equations with no real roots, but really detailing how/what is really going on. It is a great precursor to then thinking about quaternions [this video]
Cites cheeko1234 · 2018-09 · on “Walmart deploys Oculus Go headsets to train its employees”
I agree that for most of advanced math, VR won't help, however there are a lot of mathematical concepts that are easier to grasp when visualized. [LINK] [this video] [LINK]