Steven Strogatz Profile Banner
Steven Strogatz Profile
Steven Strogatz

@stevenstrogatz

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Mathematician, writer, Cornell professor. All cards on the table, face up, all the time.

Ithaca, NY
Joined May 2012
Don't wanna be here? Send us removal request.
@stevenstrogatz
Steven Strogatz
3 years
My older daughter loves sharing math memes with me. Here’s the latest:
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Steven Strogatz
4 years
Sad but true
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Steven Strogatz
3 years
Latest math meme from my older daughter
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Steven Strogatz
1 year
A great mathematician named Madhava, working in Kerala, India, discovered the power series for sin(x) in the 1300s, hundreds of years before Newton, Leibniz, Gregory, Taylor, et al. In this video, master teacher @garyrubinstein shows how Madhava did it:
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Steven Strogatz
2 years
A one-page proof of the irrationality of pi.
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Steven Strogatz
5 years
My daughter just calculated her first derivative!
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Steven Strogatz
10 years
Proof by Clementine: the surface area of a sphere is 4 pi r^2 (trace around widest part of clementine 4 times) http://t.co/Bxj2v6wpAO
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Steven Strogatz
2 years
Finally got around to watching “Spider-Man 2”. Recognize any of his textbooks? 🙋‍♂️
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Steven Strogatz
3 years
“Calm down, Pythagoras, calm down” (ht William Dunham)
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Steven Strogatz
2 years
Students taking a first course in nonlinear dynamics and chaos (or anyone curious about the subject): Videos of lectures are freely available. Hope you enjoy them!
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Steven Strogatz
5 years
The number of minutes of daylight is increasing at its maximum rate today. Happy max derivative day, everybody!
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Steven Strogatz
5 years
From one of my daughters
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Steven Strogatz
4 years
This book by Purcell was the best textbook I read as an undergraduate. It was so intellectually exciting, and had such fantastic pedagogy! I’m using relevant parts of it for my students this semester in multivariable calculus.
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Steven Strogatz
3 years
The doge rule for derivatives:
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Steven Strogatz
3 years
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@stevenstrogatz
Steven Strogatz
2 years
Now that I’m back from my trip, I’ve got access to my full wardrobe.
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Steven Strogatz
2 years
This just came in the mail today. Anything by John Stillwell is worth reading, so I’m really looking forward to dipping into his latest.
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Steven Strogatz
2 years
An elevator in the physics building at UC Santa Barbara conveniently has an accelerometer in it. I couldn’t resist going up and down a few times just to watch the changes in the effective strength of gravity.
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Steven Strogatz
1 year
You may know Prof. Gil Strang's famous book "Linear Algebra and Its Applications," or you may have watched his Linear Algebra (18.06) lectures at @MIT on YouTube. Gil's final lecture will be live streamed tomorrow at 11 am EST. Join the celebration at
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Steven Strogatz
4 years
My introductory course on Nonlinear Dynamics and Chaos is free online. Could be useful for students, teachers, and lifelong learners (or anyone needing a distraction). Prerequisites: basic calculus and physics. via @YouTube
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Steven Strogatz
4 years
A book and a letter that changed my life. After I read The Geometry of Biological Time, I wrote to its author and asked if I could come work with him. His reply, scrawled in his characteristic magic marker, led to his becoming my most important mentor.
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Steven Strogatz
1 year
Tomorrow morning at 9 am, I'll meet a new group of students in my annual course on nonlinear dynamics and chaos. After 34 years of teaching, I still get nervous before the first class -- and I'm feeling jumpy right now 😳 To all teachers and students: Have a great semester!
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Steven Strogatz
6 months
The third edition of my textbook, Nonlinear Dynamics and Chaos, was published today. You can preview the first 68 pages on Google Books, or take a look at the preface below to see what's new. The main new thing is a chapter on the Kuramoto model! Hope you enjoy it.
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Steven Strogatz
2 years
Seen in the Math Department lounge
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Steven Strogatz
4 years
In multivariable calculus, we often ask students to sketch surfaces in 3D but rarely teach them *how*. I found these helpful lessons in Thomas and Finney, Calculus and Analytic Geometry, alternate 9th edition, and plan to share them with my students. (1/2)
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Steven Strogatz
3 years
John von Neumann, a young Richard Feynman, and Stan Ulam. Three of the most original minds of the 20th century. (ht @ananyo )
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Steven Strogatz
2 years
Just started teaching residue theory. Fun!
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Steven Strogatz
4 years
@3blue1brown Her question is very good, and the answer might surprise some of you: in Al-Khwarizmi’s classic book (often regarded as the first algebra textbook), the main application of algebra is to problems stemming from Islamic inheritance law. Examples here:
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Steven Strogatz
4 years
Students taking a first course in nonlinear dynamics and chaos: My videotaped lectures are freely available on @YouTube here. Hope you find them useful. Prerequisites are elementary calculus and physics, and a little linear algebra.
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Steven Strogatz
1 year
Today in my undergraduate nonlinear dynamics class, one of my students asked to see a proof of the Poincaré-Bendixson theorem. Here's a handout of the proof that was shown to me when I was first learning about nonlinear differential equations, back in 1982.
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Steven Strogatz
4 years
Today was my first day of class, and I zoomed with the 200+ students in my "multivariable calculus for engineers" course. We had an unexpectedly wonderful session, super interactive. As you can see, I'm still on a high from it! And I want to share what worked so well... 1/n
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Steven Strogatz
6 years
Happy to announce the birth of my new book, Infinite Powers. Available for pre-order now. Due out in April in US & UK
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Steven Strogatz
4 years
Today’s my birthday. In a few weeks, my wife will celebrate hers and we will be twin primes, 59 and 61. After that we’ll have to wait 12 years for the next occurrence: 71 and 73. And after that, a long slog and a lotta luck needed to get to 101 and 103.
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Steven Strogatz
3 years
I’ve started reading this marvelous new book by Tristan Needham. It’s passionate and filled with geometrical insight, just like his earlier masterpiece VISUAL COMPLEX ANALYSIS.
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Steven Strogatz
3 years
My colleague Jim Sethna has written a wonderfully modern, interdisciplinary, and *free* textbook on statistical mechanics. He explains the big ideas and includes many cool exercises and applications.
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Steven Strogatz
3 years
Dirac and Feynman. The body language of each is so characteristic of who they were.
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Steven Strogatz
11 months
I'm teaching complex analysis right now. One of my students, Jackson Fellows, made this interactive tool to visualize complex functions w = f(z) as mappings from the z-plane to the w-plane. It currently supports +, -, *, /, (), i, exp, sin, and cos.
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@stevenstrogatz
Steven Strogatz
3 years
“Math Person” is a free verse poem by high school student Julia Schanen. Rather than try to describe it, let me just urge you to read it. It will take you a few minutes, and it will move you.
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Steven Strogatz
4 years
In movies, mathematicians are always writing on windows. In real life, these markings were made by my dog’s nose.
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Steven Strogatz
5 years
I met a remarkable boy named Zameer yesterday. He is 7, and we had fun doing math together. He started by showing me a multiplicative magic square he invented. Pretty soon we were discussing the positive minimum of the gamma function. via @YouTube .
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@stevenstrogatz
Steven Strogatz
4 years
A lot of mathematical seminars have moved online. Here’s a partial list:
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@stevenstrogatz
Steven Strogatz
3 years
Nothing original here, just an easy visual way to sum an infinite geometric series.
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@stevenstrogatz
Steven Strogatz
5 years
While waiting for my differential equations test to begin last night, one of my students (Leina Peterson) showed me a study sheet she had made for her materials science course. #breathtaking
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@stevenstrogatz
Steven Strogatz
5 years
This is why they tell you not to read your own book reviews. Thanks Howard – could you suggest a book where I could learn more about “chaos theory”?
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@stevenstrogatz
Steven Strogatz
2 years
Why do so many people get Monty Hall problem (also known the three doors problem) wrong? Steven Tijms explores both the math and the psychology in this illuminating article:
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Steven Strogatz
6 years
Mandelbrot pancake
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Steven Strogatz
6 years
Fibonacci was intimately familiar with Indian math, and “his” sequence was well known to Indian linguists and poets
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Steven Strogatz
4 years
When I was a college student, my quantum mechanics professor (Jim Peebles) used to delight us with his little jokes. I compiled a list of some of his witticisms at the time, and an old friend of mine just reminded me of it.
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Steven Strogatz
2 years
June Huh wasn’t interested in mathematics until a chance encounter during his sixth year of college. Now his profound insights connecting combinatorics and geometry have led to a Fields Medal.
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@stevenstrogatz
Steven Strogatz
4 years
Oh, the pleasures of teaching Melnikov’s method! Drawing the manifolds in real time is very stressful, but fun
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Steven Strogatz
5 years
Students taking a first course in nonlinear dynamics and chaos: My videotaped lectures are freely available on @YouTube here. Hope you find them useful. Prerequisites are elementary calculus and physics, and a little linear algebra. via @YouTube
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@stevenstrogatz
Steven Strogatz
6 years
Does this really warrant a graph?
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Steven Strogatz
3 years
My older daughter is now inundating me with math memes. Since you guys seem to like them (I’ll admit, I do too!), here are a few more.
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Steven Strogatz
2 years
"After shocking the mathematics community with a major result in 2013, Yitang Zhang now says he has solved an analogue of the celebrated Riemann hypothesis." (The analogue is called the Landau-Siegel zeros conjecture.)
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Steven Strogatz
1 year
See below for the kind of interaction on Twitter that I wish we had less of here.
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Steven Strogatz
3 years
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Steven Strogatz
2 years
Today in my complex analysis class, we're going to discuss the following infinite series. Does it converge? If so, can you evaluate it in terms of elementary functions?
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Steven Strogatz
3 years
Leftover napkin from the 60th birthday party that my wife threw for me a couple years ago
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@stevenstrogatz
Steven Strogatz
3 years
I wish I had taken Abstract Algebra from @mattmacauley when I was in college. Here’s how he teaches it: . In contrast, when I asked my teacher what I should think about when I think about groups, he said, “Think about the axioms.”
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Steven Strogatz
3 years
Quarantine math workout
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@stevenstrogatz
Steven Strogatz
5 years
Cocktail party napkins at our house
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@stevenstrogatz
Steven Strogatz
2 years
I remember being bewildered by "compactness" as a first-year college student and wish I'd had access to this article back then. Students and teachers of advanced calculus, real analysis, and point set topology may find it helpful or even illuminating.
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Steven Strogatz
8 years
The path of the sun, when you take a picture at the same time each week of the year
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Steven Strogatz
4 years
For anyone taking a first course in nonlinear dynamics and chaos this semester, you might find these lectures helpful. The prerequisites are introductory physics, and some multivariable calculus and linear algebra.
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@stevenstrogatz
Steven Strogatz
1 year
"How would you explain the concept of eigenvectors to a child?" asks @JayDeep_1729 . A few years ago I tried to do something like that – to explain eigenvectors intuitively, in five minutes, with no pictures, just words.
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Steven Strogatz
3 years
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Steven Strogatz
4 years
Happy Valentine's Day, everybody!
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Steven Strogatz
3 years
The origin of the term “random walk” (ht @dan_rockmore )
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Steven Strogatz
2 years
Secrets of the Surface: The Mathematical Vision of Maryam Mirzakhani (2020) will begin airing on U.S. public television stations starting in March 2022 in celebration of Women's History Month. Broadcast schedule: . Trailer:
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Steven Strogatz
2 years
In class today I gave the usual argument (involving drawing a bridge between two closed contours) to justify why the integral of f stays the same when we deform one contour into another through a region where f is analytic. My student Sylvan found a neat alternative argument!
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Steven Strogatz
1 year
Just finished my first class with a "dynamicist's view of the world". There's a lot to quibble about with this picture, but it helps students see where we're headed. We are going to live below the red line, in the nonlinear world, and march from n=1 to n=3.
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Steven Strogatz
4 years
What math should we be teaching in high school? Data science? Calculus? Computing? Is it time to rethink the algebra/geometry/algebra sandwich? Dan Rockmore discusses the issues in this piece featuring Steven Levitt, @joboaler , and David Coleman.
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Steven Strogatz
5 years
Free and open-source textbooks on calculus, linear algebra, differential equations, real analysis, abstract algebra, combinatorics, and introduction to proof -- a partial list, helpfully compiled and curated by Dana Ernst @danaernst .
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Steven Strogatz
2 years
In complex analysis, I'm teaching my students about "the argument principle" now. It provides info about where the zeros of a function f(z) are. Here's a toy example, using the function w = f(z) = (z-a)(z-b), where the zeros a and b are located at the black points shown below.
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Steven Strogatz
2 years
Is mathematics invented or discovered? Read what Kurt Gödel had to say. Here's the text of his 1951 Gibbs Lecture (along with an introductory note) in which Gödel argues for Platonism in the philosophy of mathematics, as in the passage excerpted below.
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Steven Strogatz
3 years
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Steven Strogatz
8 years
Hear me try to explain eigenvalues & eigenvectors intuitively, without visuals, in 5 minutes, while clarifying why they matter. Ready? Go!
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Steven Strogatz
1 year
Today in nonlinear dynamics we discussed some simple flows on a torus and made connections to number theory, knot theory, and real analysis. One student said he liked seeing all that "intersectionality". (You can see a lecture about these ideas here: )
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Steven Strogatz
3 months
Here's a graph of x^n/n! for n = 1 to 20. Can you explain why the curves look almost evenly spaced and have such similar shapes? What's the sideways spacing between them?
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Steven Strogatz
2 months
This essay is charming and insightful, but it doesn't give any hint about how to *make* discoveries. For that, I would recommend this free PDF of a book by Professor Jack Oliver, one of the discoverers of plate tectonics.
@ScholarshipfPhd
Scholarship for PhD
2 months
The importance of stupidity in scientific research
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Steven Strogatz
3 years
Just to be on the safe side…
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Steven Strogatz
4 years
Alissa Crans recently sent me a postcard featuring this gorgeous image. Can any of you decode it? I see that solid squares correspond to prime numbers. But what explains the color scheme and number of sub-rectangles in the entries for the composite numbers? #overthinking
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Steven Strogatz
5 months
This onion is connected, but not simply connected
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Steven Strogatz
5 years
Another rejection letter I'll always cherish is the following. (I had I invited myself to visit Dr. Crick – whose work on DNA topology I greatly admired – and was rebuffed in the gentlest way.) #nothing_ventured_nothing_gained
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Steven Strogatz
4 years
Maybe everybody else knows this, but I had no idea the roof of the Sydney Opera House was fashioned from a single sphere! Learn the backstory of “the Spherical Solution” here:
@misterwootube
Eddie Woo
4 years
@mathyawp @stevenstrogatz @Math4HF @yalepress The spherical solution for the @SydOperaHouse is one of the most beautiful pieces of mathematics in the world. 💛 Francis, huge congratulations on your international release of @Math4HF !!
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@stevenstrogatz
Steven Strogatz
3 years
Today is Ramanujan’s birthday. If you have never read this remembrance by his collaborator G.H. Hardy, you must read it now. (After watching THE MAN WHO KNEW INFINITY, I hear Jeremy Irons’s voice in every line.)
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Steven Strogatz
4 years
Here is the math, assuming 5% prevalence of antibodies in the population, and a 90% accurate test. Under these assumptions, the test gives the wrong result about 68% of the time among the people who test positive for antibodies.
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Steven Strogatz
4 years
Here’s my attempt to explain in plain words what eigenvectors are and why they matter, in five minutes, with no visuals. Ready? Go!
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Steven Strogatz
2 years
The Most Important Algorithm Of All Time - ⁦ @veritasium ⁩ on the Fast Fourier Transform (including a story I had not heard before, the connection between the FFT and the nuclear arms race).
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Steven Strogatz
3 years
I'm teaching a course on asymptotics and perturbation methods, and thought it might be fun to share the lectures on @YouTube . Here's lecture 1, which introduces the idea of asymptotic expansions. (For more about the course, see the rest of this thread.)
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Steven Strogatz
5 years
I've long worried about this, and it is starting to happen: Some students aren't sure which way is "clockwise" anymore. (The screenshot below is from a student's answer on a test I just gave, in which the word "counterclockwise" was used.) #DeathOfAnalog
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Steven Strogatz
4 years
What's a Tensor? - Dan Fleisch explains them here in 12 minutes using household objects. The result is a clear, intuitive, highly physical (as opposed to mathematical) view of tensors. More than 2 million people enjoyed it! via @YouTube
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Steven Strogatz
2 years
Nick Trefethen, professor of numerical analysis at @UniofOxford , explains what the concept of resonance can teach us about dribbling. Watch out, @StephenCurry30 !
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