Can you solve this geometry problem? Thanks to Lucas from Brazil for the suggestion! Kangaroo Maths 2020 https://www.matematica.pt/en/docs/kangaroo/enunciados/2020/2020_Grade9-10.pdf Proof of inscribed angle theorem https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-inscribed-angles/a/inscribed-and-central-angles-proof Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address at end of many videos). I may not reply but I do consider all ideas! If you buy from the links below I
Math
Featuring Grant Sanderson, creator of 3blue1brown. Extra footage from this interview: https://youtu.be/pJyKM-7IgAU 3blue1brown video on the shadow a cube: https://youtu.be/ltLUadnCyi0 More links & stuff in full description below ↓↓↓ 3blue1brown: https://www.youtube.com/channel/UCYO_jab_esuFRV4b17AJtAw Grant on The Numberphile Podcast: https://youtu.be/A0RH93XvSyU Numberphile is supported by the Mathematical Sciences Research Institute (MSRI): http://bit.ly/MSRINumberphile We are also supported by Science Sandbox,
Thanks to Devesh from India for the suggestion! A version of this problem was given in an Olympiad qualifying test. Socratic https://socratic.org/questions/a-root-a-b-root-b-183-a-root-b-b-root-a-182-find-9-5-a-b Math StackExchange https://math.stackexchange.com/questions/2405256/find-the-value-of-frac95ab-given-that-a-sqrtab-sqrtb-183-and-a Brainly https://brainly.in/question/3901575 Quora https://www.quora.com/Suppose-a-b-are-positive-real-numbers-such-that-a%E2%88%9Aa-+-b%E2%88%9Ab-183-a%E2%88%9Ab-+-b%E2%88%9Aa-182-How-do-we-find-9-5-a-+-b Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address at end of many videos). I may not reply but I do consider all ideas! If you buy
The Prime Number Theorem shows that primes are like weeds, popping up everywhere! Dr James Grime explains — Little bit extra cut from this video: http://youtu.be/TMRZYSQGAcw More links & stuff in full description below ↓↓↓ Our prime number video collection: http://bit.ly/primevids Follow James on Twitter at: https://twitter.com/jamesgrime NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile
Recently Russia’s Prime Minister Mikhail Mishustin visited 11th grade students (about 17-18 years old) and asked them a challenging geometry problem. Can you figure it out? I came across this puzzle in Alex Bellos’s column on The Guardian. He has a new book that I wanted to share titled “The Language Lover’s Puzzle Book.” I
An evil warden holds you prisoner, but offers you a chance to escape. There are 3 doors A, B, and C. Two of the doors lead to freedom and the third door leads to lifetime imprisonment, but you do not which door is what type. You are allowed to point to a door and ask
Is 1 a prime number? Apparently not. Dr James Grime explains. More links & stuff in full description below ↓↓↓ James Grime’s website is: http://singingbanana.com/ NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile tweets: https://twitter.com/numberphile Subscribe: http://bit.ly/Numberphile_Sub Videos by Brady Haran Patreon: http://www.patreon.com/numberphile Brady’s videos subreddit: http://www.reddit.com/r/BradyHaran/ Brady’s latest videos across all channels: http://www.bradyharanblog.com/ Sign
This problem is baffling many people on Facebook and Twitter. Can you figure it out? I thank everyone who emailed it to me, with a special thanks to the first two people: Riadh Temala from Tunisia; and Shivam Varma from India. Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Playlist to watch all videos on MindYourDecisions: https://www.youtube.com/playlist?list=UUHnj59g7jezwTy5GeL8EA_g This is the only
Tadashi explores a special set of dice… And has a powerful lesson. More links & stuff in full description below ↓↓↓ Subscribe to Numberphile: http://bit.ly/Numberphile_Sub More dice videos: http://bit.ly/Dice_Videos Playlist of Tadashi Tokieda videos: http://bit.ly/tadashi_vids Want to buy some dice like this – our friends at Maths Gear have some: http://bit.ly/MathsGearDice Discuss this video on
Extended math version: http://youtu.be/ugbWqWCcxrg?t=2m32s A version for Dummies: https://youtu.be/7u6kFlWZOWg More links & stuff in full description below ↓↓↓ This video features Lisa Goldberg, an adjunct professor in the Department of Statistics at University of California, Berkeley. Support us on Patreon: http://www.patreon.com/numberphile NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile tweets: https://twitter.com/numberphile Subscribe: http://bit.ly/Numberphile_Sub Numberphile is
In a square, a line is drawn from the bottom left corner with length 12 to the interior of the square. From the end of that line, a perpendicular is drawn going up and left with length 3. From the end of that line, another perpendicular is drawn going up and right with length 9.
Featuring Professor Edward Frenkel. Here is the biggest (?) unsolved problem in maths… The Riemann Hypothesis. More links & stuff in full description below ↓↓↓ Prime Number Theorem: http://youtu.be/l8ezziaEeNE Fermat’s Last Theorem: http://youtu.be/qiNcEguuFSA Prof Edward Frenkel’s book Love and Math: http://amzn.to/1g6XP6j Professor Frenkel is a mathematics professor at the University of California, Berkeley – http://edwardfrenkel.com
This is a nice little logic puzzle from Terry Stickels! Books by Terry Stickels (including “Contemporary Brainteasers”) http://www.terrystickels.com/books.html Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address in video). I consider all ideas though can’t always reply! Like many YouTubers I use popular software to prepare my videos. You can search for animation software tutorials on
A bit about zero – including a discussion of its even-ness!? More links & stuff in full description below ↓↓↓ Featuring Dr James Grime (https://twitter.com/jamesgrime) and Professor Roger Bowley (University of Nottingham). NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile tweets: https://twitter.com/numberphile Subscribe: http://bit.ly/Numberphile_Sub Videos by Brady Haran Patreon: http://www.patreon.com/numberphile Brady’s videos subreddit: http://www.reddit.com/r/BradyHaran/ Brady’s
Thanks to John H. for the suggestion! A square is inscribed in a quarter circle with two of its vertices on the arc. If the radius equals 1, what is the area of the square? Special thanks this month to: Robert Zarnke, Kyle, Mike Robertson, Michael Anvari, Daniel Lewis. Thanks to all supporters on Patreon!
What is the area of the square? Thanks to Papa in India for the suggestion! This puzzle is half of of problem 21 in the 2017 AMC 10A. https://artofproblemsolving.com/wiki/index.php/2017_AMC_10A_Problems/Problem_21 Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address in video). I consider all ideas though can’t always reply! Like many YouTubers I use popular software to
Famously beautiful, the Mandelbrot Set is all about complex numbers. Featuring Dr Holly Krieger from MIT. More links & stuff in full description below ↓↓↓ The next part is on Numberphile2 at: http://youtu.be/oCkQ7WK7vuY Animation courtesy of team fresh. Check out more at: http://hd-fractals.com — Music: Alan Stewart. Support him at http://bit.ly/1sdwTHF More videos with Holly
Fermat’s “Little” Theorem is great – but beware of Fermat Liars and tricky Carmichael Numbers. More links & stuff in full description below ↓↓↓ Continues at: http://youtu.be/HvMSRWTE2mI Featuring Dr James Grime – https://twitter.com/jamesgrime Support us on Patreon: http://www.patreon.com/numberphile NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile tweets: https://twitter.com/numberphile Subscribe: http://bit.ly/Numberphile_Sub Numberphile is supported by the
To complete a job, it takes: Alice and Bob 2 hours, Alice and Charlie 3 hours, and Bob and Charlie 4 hours. How long will the job take if all 3 work together? Many, many US college students set up the equations incorrectly and get the wrong answer. Can you solve it? Watch the video
Learn one weird trick to solve this problem! Thanks to Nestor Abad for alerting me of a typo in an earlier version of the video. Reference https://socratic.org/questions/if-x-sqrt-x-2-1-y-sqrt-y-2-1-1-what-is-x-y Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address in video). I consider all ideas though can’t always reply! Like many YouTubers I use popular software to prepare my
Dividing by zero, zero divided by zero and zero to the power of zero – all pose problems! More links & stuff in full description below ↓↓↓ This video features Matt Parker and James Grime – https://twitter.com/standupmaths and https://twitter.com/jamesgrime NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile tweets: https://twitter.com/numberphile Subscribe: http://bit.ly/Numberphile_Sub Videos by Brady Haran
Dr James Grime discusses a couple of clever formulas which are pandigital – using all the numbers from 1-9. More links & stuff in full description below ↓↓↓ More on pandigital numbers: https://youtu.be/gaVMrqzb91w More on e: https://youtu.be/AuA2EAgAegE More James Grime videos: http://bit.ly/grimevideos Book James for a talk: http://jamesgrime.com The contest which gave us these formulas:
Can you solve this equation? Thanks to Hrigved for the suggestion! Reference https://math.stackexchange.com/questions/438452/find-all-real-numbers-such-that-sqrtx-frac1x-sqrt1-frac1x Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address at end of many videos). I may not reply but I do consider all ideas! If you buy from the links below I may receive a commission for sales. (As an Amazon Associate I
Can you estimate the log of 3 to the base of 2 without using a calculator? This kind of skill is actually pretty important in university mathematics. Watch the video to learn how to solve it! Source https://www.quora.com/How-do-you-solve-this-question-from-Oxfords-Math-Admissions-Test-No-calculators Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address in video). I consider all ideas though can’t always
Matt Parker reveals his pride and joy – the mysterious Parker Square! More links & stuff in full description below ↓↓↓ Merch: https://numberphile.creator-spring.com/listing/the-parker-square More magic square videos: http://bit.ly/MagicSquareVideos Matt Parker: https://www.youtube.com/standupmaths Audrey (Brady’s chihuahua): https://youtu.be/s84dBopsIe4 Support us on Patreon: http://www.patreon.com/numberphile NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile tweets: https://twitter.com/numberphile Subscribe: http://bit.ly/Numberphile_Sub Numberphile is supported
Many tests around the world include a problem like this. How can you calculate this quickly, without making any mistakes? Thanks to all patrons! Special thanks to: Ertugrul Oruç, Michael Anvari, Richard Ohnemus, Shrihari Puranik, Kyle. Source https://twitter.com/thebapex/status/1149020375189270528 Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address in video). I consider all ideas though can’t always
A game to play on the elliptical table: http://youtu.be/3WHBlPvK3Ek More links & stuff in full description below ↓↓↓ And more extra footage: http://youtu.be/pulp55gTKGE Alex Bellos’ Loop Table website: http://www.loop-the-game.com Alex discusses the topic in his book Alex Through the Looking-Glass (UK) and The Grapes of Math (US)… http://bit.ly/BellosBooks Support us on Patreon: http://www.patreon.com/numberphile NUMBERPHILE Website:
Marcus du Sautoy discusses Gödel’s Incompleteness Theorem More links & stuff in full description below ↓↓↓ Extra Footage Part One: https://youtu.be/mccoBBf0VDM Extra Footage Part Two: https://youtu.be/7DtzChPqUAw Professor du Sautoy is Simonyi Professor for the Public Understanding of Science and a Professor of Mathematics at the University of Oxford. Professor du Sautoy’s book as mentioned… In
Can you solve this tricky math problem? Thanks to Asad for the suggestion! Art of Problem Solving 2019 AIME Problem 3 (there are many solution methods) https://artofproblemsolving.com/wiki/index.php/2019_AIME_I_Problems/Problem_3 Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address in video). I cannot reply to everyone but I consider all ideas! Like many YouTubers I use popular software to
Thanks to Surjadi from Indonesia for the suggestion! Twitter Cshearer41 A square is split into five rectangles with equal areas. What’s the area of the square? pic.twitter.com/wtuEjxMASI — Catriona Agg (@Cshearer41) July 11, 2020 solution by @birkhofyan pic.twitter.com/3EIij7DjaU — Birkan Yıldız (@birkhoff_math) July 11, 2020 Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address in video).
Catch David on the Numberphile podcast: https://youtu.be/9y1BGvnTyQA Professor David Eisenbud on the infamous Collatz Conjecture, a simple problem that mathematicians may not be “ready” to crack. More links & stuff in full description below ↓↓↓ Extra footage from this interview: https://youtu.be/O2_h3z1YgEU Prof Eisenbud’s 17-gon: https://youtu.be/87uo2TPrsl8 Support us on Patreon: http://www.patreon.com/numberphile NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on
We now have a Tumblr: Tumblr: http://numberphile.tumblr.com This paper on ebay: http://www.ebay.co.uk/itm/221197137799? More links & stuff in full description below ↓↓↓ Just how hard was the second problem cracked by Will in Good Will Hunting? Matt Damon! And who doesn’t love Homeomorphically Irreducible Trees? This video features Dr James Grime – http://singingbanana.com/ Music by Alan
This is a tricky geometry problem with an elegant solution! Sources Adapted from past SEAMO problem (emailed to me) Cut The Knot similar problem https://www.cut-the-knot.org/proofs/swivel.shtml Quote A Technique is Just a Trick That Went Viral Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address in video). I consider all ideas though can’t always reply! Why are
Learn the trick to this challenging algebra problem. Thanks to Ritwick in India for suggesting this problem! It comes from an IIT JEE sample paper (the JEE tests are used for admission into India’s prestigious IIT colleges). Reference https://socratic.org/questions/how-do-you-solve-6-x-4-x-9-x Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address in video). I consider all ideas though can’t
See our other Graham’s Number videos: http://bit.ly/G_Number More Ron Graham Videos: http://bit.ly/Ron_Graham More links & stuff in full description below ↓↓↓ The magnitude of Graham’s Number is difficult to fathom – Ron Graham himself attempts to explain. WHAT IS the number: http://youtu.be/HX8bihEe3nA Extra footage: http://youtu.be/rGWuimr5CGQ Our original Graham’s Number video: http://youtu.be/XTeJ64KD5cg Any errors in this
Can you solve for the area of the square and the length of the tangent line? Special thanks this month to Fiona Harper, Kyle, Mike Robertson, Michael Anvari, Robert Zarnke. Thanks to all supporters on Patreon! http://www.patreon.com/mindyourdecisions Adapted from a puzzle by Twitter @Cshearer41 (Catriona Agg) A semicircle and quarter circle inside a square. How
A million digits of Pi on one piece of paper (1.05 miles). More links & stuff in full description below ↓↓↓ More about how and why: http://youtu.be/99Welatppzk More Pi videos from Numberphile: http://bit.ly/PiPlaylist Film by Brady Haran Our thanks to HP and HSA Systems. Extra special thanks to Hugh McPartlan, Torben Dam Jensen, Jesper Hyldager
This is a pretty tricky problem. Can you solve for the angle? Watch the video for the solution. I thank Barry, and I thank Akshay Dhivare from India for suggesting the problem via email. Sources https://gogeometry.blogspot.com/2008/05/elearn-geometry-problem-10.html Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Playlist to watch all videos on MindYourDecisions: https://www.youtube.com/playlist?list=UUHnj59g7jezwTy5GeL8EA_g This is the only channel to feature math topics
Banks, Facebook, Twitter and Google use epic numbers – based on prime factors – to keep our Internet secrets. This is RSA public-key encryption. More links & stuff in full description below ↓↓↓ Gold Vault: https://youtu.be/CTtf5s2HFkA This video features Dr James Grime (http://singingbanana.com/). Message from James: “Thanks to Dr Chris Hughes of the University of
Who can solve this one? Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address in video). I consider all ideas though can’t always reply! Like many YouTubers I use popular software to prepare my videos. You can search for animation software tutorials on YouTube to learn how to make videos. Be prepared–animation is time consuming and
Featuring Tadashi Tokieda – more Tadashi videos at: http://bit.ly/tadashi_vids More links & stuff in full description below ↓↓↓ Tadashi Tokieda is a Professor of Mathematics at Stanford University (though this was filmed when he was at Cambridge, in the UK). Animation by Pete McPartlan. Numberphile is supported by the Mathematical Sciences Research Institute (MSRI): http://bit.ly/MSRINumberphile
The flaw which allowed the Allies to break the Nazi Enigma code. More links & stuff in full description below ↓↓↓ First video explaining Enigma: http://youtu.be/G2_Q9FoD-oQ Extra footage: http://youtu.be/BdrrJ7qd4HA Brown papers on ebay: http://bit.ly/brownpapers Periodic Videos: http://www.youtube.com/periodicvideos This video features Dr James Grime discussing Enigma, the Bombe and Alan Turing. James’ “day job” is touring
Thanks to Taka for the suggestion! This is a fun and challenging geometry problem. Special thanks this month to: Michael Anvari, Kyle. Thanks to all supporters on Patreon! http://www.patreon.com/mindyourdecisions Source https://twitter.com/panbtc/status/1232235184335908864 Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address in video). I consider all ideas though can’t always reply! Like many YouTubers I use popular
Numbers like e and Pi cannot be made using normal algebra. Featuring Australia’s Numeracy Ambassador, Simon Pampena. Extra footage: http://youtu.be/dzerDfN2E7U More links & stuff in full description below ↓↓↓ Discussing transendental numbers, algebraic numbers, pi, e and other stuff. Simon’s website: http://www.numbercrunch.com.au/ Root 2: http://www.youtube.com/watch?v=5sKah3pJnHI Pi Playlist: http://www.youtube.com/playlist?list=PL4870492ACBDC2E7C NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile
Many people requested this one. It was asked to 9th grade students in India who had only learned geometry, so you are supposed to solve it without using trigonometry. I thank Anand Gautam for discovering the incredible solution! Polish translation credit: Tłumaczenie: Przemyslav Znajdź mnie tutaj: https://forum.cdaction.pl/blogs/blog/64401-ma%C5%82a-wie%C5%9B-po%C5%9Brodku-niczego/ You can also solve the problem with trigonometry.