Summer of Math Exposition

Presented by 3Blue1Brown 3blue1brown

Why is the area under 1/x a logarithm?

Audience:

Tags: logarithmshyperbola

Why is the area under this hyperbola a logarithm? Why is the base of this logarithm the number e? Why is that so important this is called "natural logarithm"? You'll find all the answers in this video. This content is mainly aimed towards undergraduate students. It touches a bit on integrals towards the end of this video, but the explanation is mainly visual, using the concept of "hyperbolic rotation" to explain why area(a), i.e. the area between 1 and a, has the property that area(a) + area(b) = area(ab): the logarithm property, as well as using the same concept to find the base of that logarithm.


Analytics

6.46 Overall score*
56 Rank
10 Votes
8 Comments

Comments

6.5

Introducing hyperbolic rotation to motivate this natural logarithm is a strong start. However since you spend the rest of the video using it, a bit more introduction and getting familiar to it would have helped a lot.

6

Cool idea. The explanation initially about the rotation could have been better. Nice visualizations, thanks for the explanation…

4

It’s not very clear why the area under the curve from u to v is preserved when multiplying both u and v by a constant, you only show it for a rectangle from the origin to a point in the curve.

8

I don’t speak spanish (or portugese?) but I really enjoyed watching this video. I think it’s extremely useful for students to learn where these wierd functions come from when differentiating. I think this video also fits perfectly into the goal of this years SoME, that is, focusing more on high school math.

8.4

Really good video explaining the area under 1/x. And nice Lord of the Ring reference there!

6.5

I like where it starts going, but I feel like it doesn’t really draw a good connection, and rather defines properties of e, logs and particularly the natural logartith instead of coming back as to WHY is it specifically related. Good visuals and very concise

5.8

I didn’t really understand the connection between ln(x) and 1/x before, but this video helped. I liked how the video showed that the logarithm satisfies this condition of area under the curve of 1/x, which was introduced rather naturally and neatly.

6.8

Excellent job with pace and flow of the video, as well as its straightforward approach for undergrads. This video helped emphasize the universality of mathematics. This video was produced in Spanish, so I had CC in English, and the familiary of the Manim library helped me understand the relation of hyperbolic rotation to ln and e. I’ve set your Ranking score as an average of thes individual scores, good luck: Motivation: 9 Clarity: 5 Novelty: 5 Memorability: 8