![Jim Simons](/img/default-banner.jpg)
- Видео 21
- Просмотров 38 543
Jim Simons
Великобритания
Добавлен 23 сен 2020
I love to share mathematical ideas with other people, be they students or fellow teachers. The channel is devoted to pieces of mathematics I particularly enjoy, mostly in or around the English A level or Scottish Higher syllabus. It grew out of my talks at the annual conference of the Mathematica Association, and so mostly the viewer I have in mind is another teacher of these topics. In some cases my ideas might give you some new insights or enrichment ideas to help directly with your teaching, but more often I'm just sharing ideas I love, and hoping you will enjoy them. Students may also enjoy these videos, but for the ones that cover material in the syllabus, it's probably better to look at the videos after learning the topics at school - these are not really tutorials. Some of the topics are way off the syllabus though, and anyone might enjoy them. I have a particular interest in the history of mathematics.
Subtracting Left to Right
I teach you how to subtract two multi-digit numbers working from the left to the right. You might think that is impossible, but watch! If you learn this method and practice a little, I think you will find it easier than the standard right-to-left method. I also think it makes it easier to understand WHY the answer is what it is. What'd not to like?
Просмотров: 180
Видео
From Cubics to Complex Numbers
Просмотров 3345 месяцев назад
We all know the formula for solving quadratics, but there is also a formula for solving cubics. It's a pretty piece of mathematics, and its discovery, in the sixteenth century, is thought by many to be the start of modern mathematics, because it sowed the seed that led to complex numbers. In this video I show how to solve cubic equations, and follow the story of the development of complex numbers.
Trigonometry and its History IV: Prosthapaeresis, the First Fast Multiplication Algorithm
Просмотров 1847 месяцев назад
I explain phrosthaphaeresis, a method for rapid multiplication that was invented in the sixteenth century, and was used before logarithms superceded it at the start of the seventeenth century. It uses ideas from trigonometry that go back to Ptolemy of Alexandria in the second century. I then time it, comparing it with ordinary multiplication and with logarithms, for 4-figure multiplication and ...
Trigomometry and Its History III - Trigonometry Meets Calculus and They Make Waves
Просмотров 13010 месяцев назад
We leave angles, and indeed geometry, behind, as Sin and Cos become waves - usually functions of time rather than an angle. Along the way we develop the theory with slightly more rigour than school text books usually do, and as usual explore the history of these ideas.
Trigonometry and Its History II - Obtuse Angles and the Curious History of the Cosine Rule
Просмотров 175Год назад
I talk about how I like to develop trigonometry, give some of my favourite proofs, and explore the history. The history of the sine rule is simple - it' over 1300 years old. The cosine rule took much longer and was only fully formed some 200 years ago. I explore why that is.
Babylonian Mathematics
Просмотров 1,4 тыс.Год назад
A short look at the extraordinary mathematics of Ancient Babylon, from nearly 4000 ago. We see their base 60 number system and some of the things they could do with it. At the end we examine the amazing clay spreadsheet that is Plimpton 322, which is a sort of precursor of trigonometry.
Trigonometry and its History - 1. right angled triangles
Просмотров 410Год назад
Aiming for enrichment of school mathematics, I tell the history of elementary trig from ancient Greece to India, and back to Europe. We meet a Babylonian spreadsheet all about Pythagoras's theorem, well over 1000 years before Pythagoras. We find that the first trigonometry didn't have right angled triangles at all, but only a circle and a chord. I tell the mysterious story of how sine got its n...
Tidal Destruction
Просмотров 662 года назад
The forces that cause the tides and slow the moon down, can also destroy things, fir example grinding up comets to create Saturn's rings. We lok at how that works
Tidal Locking
Просмотров 982 года назад
The forces that cause the tides have also caused the moon's spin to slow right down so that it always show us the same face. We'll look at how that works, and also see why Mercury's day is twice as long as its year, a curious phenomenon caused again by tidal forces
How the tides work in the oceans
Просмотров 1492 года назад
Many of the explanations of the tides are wrong, and even when they are right they are nevertheless misleading. This video does it right, and that requires some mathematics.
Three pretty geometric theorems, proved by complex numbers
Просмотров 26 тыс.2 года назад
Bottema'a theorem, van Aubel's theorem and Napoleon's theorem, are all brilliant. If you have never seen them before, you will be amazed! I prove then all by working in the complex plan, as van Aubel did in 1878.
Modular Arithmetic Part Two - A Tale of Two Triangles and the Chinese Remainder Theorem
Просмотров 1302 года назад
A follow-on from my previous video, "Modular Arithmetic and Checksums". This video explores some more ideas using modular arithmetic, including a surprising connections between two famous triangles, and the famous and ancient Chinese Remainder Theorem
Sundials and the Equation of Time
Просмотров 7 тыс.2 года назад
I explore the basic features of a sundial, and then explain the shape of the "Equation of Time" which converts solar time into clock time.
Modular Arithmetic and Checksums Part One
Просмотров 4692 года назад
5 hours after 10 o'clock it's 3 o'clock. So in some sense, 10 5 = 3. That sense is called modular arithmetic. In this video I explore this form of arithmetic, and look at its application to checksums, such as the last digit on a bank card number.
How We Used Log Tables
Просмотров 8573 года назад
A description of how we used to use 4-figure log tables to do calculations. Also other 4-figure tables and 7-figure log tables. Some stuff about how common logarithms, ie logs to base 10, are relevant to today's education - for getting a grip on what exponentiation growth is like, and for mental Fermi estimating.
The Chain Rule - How to REALLY Understand It
Просмотров 6703 года назад
The Chain Rule - How to REALLY Understand It
Graph transformations beyond your dreams
Просмотров 1273 года назад
Graph transformations beyond your dreams
Thank you, well laid out and explained! I read the book 'Negative Math: How Mathematical Rules Can Be Positively Bent' by Martinez and was quite confused and amazed about how, as you say, 'aliens on another planet' might have done alternative maths where -1*-1=-1. Quite crazy
Thank you! It is pretty simple. I thought it would have been harder to understand.
Very enjoyable video. Thank you.
Fantastic video!
Amazing!
Definitely cool video but I think it is important to point out that complex numbers are in no way necessary for these proofs, and this isn't even really justification for the utility of them, since I'm pretty sure the proofs could just be phrased in terms of the basic rotation formulas and vectors. The complex numbers just provide a convenient and natural shorthand.
Very nice way to show different perspectives and their pros and cons.
Brilliant man, this is a great video.
Nice demonstration. But in case of Napoleon's Theorem, it is sufficient to prove that the lengths of the side of the triangle are equal, you don't need to introduce rotation over 120º.
What’s the Mac app you’re using?
Geogebra
What software are you using?
geogebra
RIP Jim.
I'm not that Jim Simons!
Paraphrasing Mark Twain, reports of your demise are over-emphasized, correct? Good to hear it, Mr. Jim.
love the napoleon bit
I used to prove random common Euclidean geometry problems with complex coordinates. Works much better than real coordinates most of the time though not always better than using theorems
Beautiful!
Absolutely gorgeous video. We need more of this on RUclips.
The maths for napolean's theorem works out cleaner if you use w instead of i, see the wikipedia page on eisenstein integers for more info: en.wikipedia.org/wiki/Eisenstein_integer
I don't get the 1/sqrt(3) bit. Half the height of an equilateral triangle of side length 2(y-x) is [sqrt(3)/2]*(y-x)
yes but the center is not at half the height, but at one third of it.
do you have similar intuition for the product rule?
Nice video!
While napoleon waged war throughout Europe, hippolite Charles made love to Josephine in the imperial bed!! Napo couldn't figure it out!!!
I'm surprised the anti-science people who deny that the moon rotates haven't infiltrated this comment section.
I knew there is a better method for this! Thank you, that is really a great video and a much more powerful method than the normal one.
At the very start of the video you show two different "implementations" of Pythagoras's Theorem, which I took to be the same, as I didn't know that it was an evolution to joint geometry and algebra. If both representations are equivalent, I assume, that Euclidean Norm is implied. I also assume, that a right angled triangle is still the same if placed in a plane and moved around or rotated. Now the question: If I move the triangle and the shape changes, then the equivalence of both representations is no longer given. And is it right to say: an object changing shape when rotated is not an valid object under the algebraic and geometric relationship? (I know the wording is not "conventional" as math and English is not my native language ;-) )
Very interesting - I will use this method from now on. Thank you!
Excellent, that's one convert so far!
That is very cool
Some comment should mention the Petr-Douglas-Neumann theorem in this context. Allow me to. I knew about the theorem but had forgotten its name. Thanks for triggering me to look it up again. Wonderful little tidbit that!
Yes, that's a great theorem.
@@jimmathy And not a week later another video comes out ( ruclips.net/video/WLAW5yz5O3E/видео.html ) on the same. Nice combo of coincident videos!
Really appreciate your vdeos❤
Thank you!
Hello! Im from Brazil, and i am studying olimpiad's mathematic to get a medal at OBM and maybe, go to IMO. I was with difficult in geometry with complex numbers, but after your video (a video you sent 2 years ago) i understood! Dont stop making your videos, they are very good and could help another students with the same problem as me!
I believe the last theorem is where Symmetrical Components in Electrical Engineering come from. Representing a 3-phase unbalanced system by the superposition of three balanced systems.
Wow, that's intrguing! However, I don't know anything about Elecrical Engineering, so I can't comment.
Thank you.
That's really very neat, how you can use the half angle formula to carry the exact values all the way down as finely as you like. And then as soon as you get to a fine enough resolution to ensure the accuracy you want, you can use finite differences to interpolate in between that last round of exact values, to get your table entries on whatever spacing you want. I may have to write a Python program to do this. Maybe generate a nice LaTeX table set. 🙂 Or heck, even just a plain text set.
Well, it's more sensible for US to measure angles using decimal degrees, since we count in base 10. It made more sense for the Babylonians to do exactly what they did.
Indeed. The wonder is it took getting on for a thousand years from when decimal fractions arrived in Europe before we switched from sexagesimal to decimal for degres,
Ware the past scientists of Indian origin?
Thank you for a very dense and precise explanation of the equation of time. My interest stems from wanting to understand watches with the equation of time complication and how clocks are (or at least were) used for navigation. Having watched a couple of videos whose explanation didn’t really make sense to me, thank you for making a video that makes the issues crystal clear, though still not easy. It’s also nice to see the concept of precession applied.
Thanks.
This was fascinating - thank you!
Thanks. I'm glad you enjoyed it.
Too bad, the youtube algorithm does not guage quality. This video should be top of the list when looking for chain rule.
Thank you!
Thank you!
Excellent! I really enjoyed this and definitely learned a lot. There were many, many pauses for the brain to catch up...
Glad it was helpful!
I always thought that Solar time = clock time. Maybe because I live near the equator where day = night throughout the year.
On the equator, hours of daylight are always close to hours of darkness, though not exactly. But the equation of time and the analemma are the same the world over.
I used complex numbers miners to find all the 3rd points of similar triangles with two fixed points. It was a Riemann sphere.
It's funny to me that modular arithmetic was a major revelation to modern conputer scientists, whereas ancient babylonians were so comfortable with the idea of the modular multiplicative inverse that it was built right into the way they wrote numbers. 10 and 1/6 aren't just represented the same way, they act as the exact same number because 10 and 6 are each other's MI mod 60. That's hardcore AF.
Very nice geometric problems . It is also good to see ,especially for people who didn't like complex numbers , how much you can achieve by a clever application of them.
My opinion of this video can be summed up by the following: complex numbers fucking rock! Repurposing algebraic machinery to perform geometric calculations, the elegance of it is astounding.
brilliant! now how can one go about proving concurrency of lines using complex numbers?
😮😮😮 beautiful theroems
This is really interesting! Thank you for explaining. I want to get my hands on a 4 figure log table book now.
Thanks. I think there are plenty of 4 figure tables for sale.
just found the channel, good stuff, please keep going
What was the software used in this video?
I used geogebra.
Waterloo
So cool ❤
Marvelous and memorable.
Thanks