Wrong, But Useful: Episode 46

In this month's edition of Wrong, But Useful, @reflectivemaths and I are joined by special guest co-host @dragon_dodo, who is Dominika Vasilkova in real life. We discuss:

  • What maths appeals to a physicist.
  • Dominika's number of the podcast: $0.110001000000000000000001...$, Liouville's constant, which is $\sum_{n=1}^\infty 10^{-n!}$, the first constant to be proved transcendental.
  • Megaminxes
  • Sad news: Fields Medallist Maryam Mirzakhani has died from cancer aged 40. Here is an interview with her from a couple of years ago.. We discuss our chances of winning next year's Fields Medals. Colin is too old, but Dave and Dominika are in the running. Colin can, however, namecheck several Fields Medallists from memory.Medicine instructions
  • Big Mathsjam registration is open. It's a few days before Colin's 40th birthday and you should go. You can get early bird prices usually until around mid-August.
  • Dave has a beef about the Nurofen instructions. We have suggestions for them.
  • SET and why the odds in the instruction booklet are a bit wrong
    You can play SET here. We also discuss Dobble.
  • Dave discusses the tessellation of three regular polygons. For clarity, there are more than two possible three-tessellations at a point.
  • Thanks to @chrishazell72 for this from Kac and Ulam, who are mentioned in Cracking Mathematics (available wherever good books are sold): “Statistics is not a branch of mathematics….” Stats is not maths - Kac and Ulam
  • Colin has an article in Chalkdust!
  • Dave has a challenge for his students: "Make 8." Is that a good question?
  • Puzzle feedback: gold stars to @chrishazell72, @dragon_dodo, @fenneklyra, and loyal listener Sam Steele who sent the correct answer on a postcard: spinning the revolver gives Bond a $\frac {1}{3}$ probability of dying, but not spinning gives him only a one-in-four chance, so he should not spin. Chris Hazell also wonders if the weight of the bullets might bias the spin! Dave wonders how it changes if you only know there are two bullets somewhere in the revolver. He asked the question on his blog some time ago.
  • This month's puzzle: your password needs to contain at least four distinct digits, but no digit more than three times. You pick a nine-digit number at random. What’s the probability you picked a valid password?
  • Dave suggests we drop the "... in real life". That's clearly preposterous, but in the spirit of openness, we invite your comments.


Colin is a Weymouth maths tutor, author of several Maths For Dummies books and A-level maths guides. He started Flying Colours Maths in 2008. He lives with an espresso pot and nothing to prove.


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