Imaginary Numbers Are Real [Part 1: Introduction]
Welch Labs7 HN recommenders · recommended in 7 months, 2017-2025
8.6M views · 11 years ago · course · evergreen
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.
HN commenters rate the series as some of the best visual teaching on complex numbers and recommend it for building intuition.
23:29How Imaginary Numbers Were Invented
Veritasium
22.7M views • 5 years ago
12:25Fantastic Quaternions - Numberphile
Numberphile
1.1M views • 10 years ago
11:26Do Complex Numbers Exist?
Sabine Hossenfelder
854K views • 5 years ago
15:08What does it feel like to invent math?
3Blue1Brown
4.6M views • 11 years ago
34:25Ramanujan: Making sense of 1+2+3+... = -1/12 and Co.
Mathologer
3.6M views • 10 years ago
7:27Sloane's Gap - Numberphile
Numberphile
1.5M views • 13 years ago
31:51Visualizing the 4d numbers Quaternions
3Blue1Brown
5.6M views • 8 years ago
1:02:06Real Analysis, Lecture 1: Constructing the Rational Numbers
HarveyMuddCollegeEDU
613K views • 16 years ago
57:03HACKENBUSH: a window to a new world of math
Owen Maitzen
562K views • 5 years ago
17:05The essence of calculus
3Blue1Brown
11.9M views • 9 years ago
29:43Pi hiding in prime regularities
3Blue1Brown
2.8M views • 9 years ago
12:35The Mathematics of Quantum Computers | Infinite Series
PBS Infinite Series
718K views • 9 years ago
44:23A Swift Introduction to Geometric Algebra
sudgylacmoe
1.1M views • 6 years ago
5:09Essence of linear algebra preview
3Blue1Brown
2.8M views • 10 years ago
51:16What is Euler's formula actually saying? | Ep. 4 Lockdown live math
3Blue1Brown
1.7M views • 6 years ago
22:21Why do prime numbers make these spirals? | Dirichlet’s theorem and pi approximations
3Blue1Brown
7.6M views • 7 years ago
24:28Euler's formula with introductory group theory
3Blue1Brown
2.8M views • 9 years ago
17:16Eigenvectors and eigenvalues | Chapter 14, Essence of linear algebra
3Blue1Brown
6.4M views • 10 years ago
41:44Numberphile v. Math: the truth about 1+2+3+...=-1/12
Mathologer
3.3M views • 8 years ago
7:42Extremely Large Numbers 1 - Introduction
Giroux Studios
20K views • 11 years ago
9 comments from Hacker News
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
Regarding imaginary numbers, I found this YouTube series really helpful to understand basics of imaginary numbers. ▶ this video
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
Welch labs has an amazing series on complex numbers called “imaginary numbers are real”. Great explanations, engaging content and high production value. ▶ this video
For a small buffet of abstract math topics (with lots of exposition putting ideas into historical context and an emphasis on building geometric intuition) try Courant & Robbins "What is Mathematics?". Covers number theory, number systems, geometry, topology, optimization, algebra, and knots, among others. You could also play around with branches of math like Knot and Braid Theory, which are interesting in their own right, give insight into lots of different branches of math, and many interesting problems are still accessible to lay people. Number theory is also like this I think it can also be helpful to learn some things about the history of math and the historical context that different ideas came from. Here's a nice example covering complex numbers ▶ this video Maybe tangential to your ends, but the Crest of the Peacock is a nice book on non-European mathematical traditions, which provides some insight into how the process of establishing and validating mathematical knowledge works in other cultures. You might try books written by physicists or that are about mathematical physics (an author to look out for depending on your level is VI Arnold), since arguments will be of a more geometric or physical nature and appeal more to intuition. Stillwell is another author (not a physicist) that tends to write books that give context and geometric intuition You might like playing around with Pinter & Humphreys for Algebra, or Jänich for Topology (fantastic book for building intuition aro
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
I really enjoyed this video series on imaginary numbers. Went through the history as well as the math: ▶ this video
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.
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