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What is Euler's formula actually saying? | Ep. 4 Lockdown live math

3Blue1Brown · 1.7M views · 2020-04-28 · 51:16

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Overview

A 3Blue1Brown live lockdown math episode asking what Euler's formula e^(pi i) is actually saying. It builds intuition through exponentials, rotation and vectors landing on the unit circle.

On Hacker News

HN recommends it as the explanation that makes complex exponentials click, especially for understanding the Fourier transform.

Recommended by 1 HN people across 1 months · HN mentions 2020–2023

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What people said

rectang · 2023-01 · Strong recommendation

The key insight for me on this topic also came from 3Blue1Brown, but in a different video: it’s that e^x is NOT best thought of as repeated multiplication, but instead as the function exp(x) = 1 + x + x^2/2 + X^3/6 + x^4/24 + … After being relieved of the burden of that misconception, I was finally able to understand the role of complex numbers in the Fourier Transform. [VIDEO]

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rectang · 2023-01 · Recommendation

People told me that over and over but it didn’t help — because it didn’t make sense why repeated multiplication would cause rotation! Later in that video, we see a visualization of the rotation. I was able to grasp how the exp function could yield rotation where I’d never been able to understand why e*e*e*e… did. [VIDEO]

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beforeolives · 2021-06 · Reference

I think that e^(i*pi) + 1 = 0 is massively overrated. Because the beauty that people find is largely based on the symbols that are present and because it doesn't really say anything meaningful beyond itself. It's not even a formula or an equation - it's a result. It's like being impressed by cos(pi) = -1. The more general formula e^(ix) = cosx + i*sinx is a lot more impressive. Both because of it's implications for the rest of mathematics and aesthetically. If you look at the way the vectors at 38:00-39:20[1] cancel out to always land on the unit circle - I can get behind calling that beautiful. [1] [VIDEO]

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Video by 3Blue1Brown, played through YouTube.

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