# October, 2019

## Ask Uncle Colin: A Partition Enigma

Dear Uncle Colin, In reading Sir Dermot Turing’s XY&Z, he states that the number of species of cycle is 101 - and after a bit of thought, I figured out that that’s the number of partitions of the number 13. However, I couldn’t work out how to get 101! Can

## The Mathematical Ninja and the *Other* Pole

“Sensei, why have you covered the entire Earth in an area-preserving wrap?” “It’s all @colinthemathmo's doing.” “I’m surprised you’re doing it in hardware rather than working it out in your head.” “Oh, $\frac{1000}{\sqrt{\pi}}$? That’s trivial.” “But of course it is.” “I mean, $\frac{1}{\pi}$ is pretty close to $\sqrt{1}{\frac{10}}$, which is

Dear Uncle Colin, I have a probability question that involves a weird place where every family has three children, and every child is either a girl or a boy. 50-50. Independent of each other. If I take a random family, and choose at random one of the children, I have

## Dictionary of Mathematical Eponymy: Johnson Solids

I am a big fan of polyhedra. I’ve raved elsewhere about the icosidodecahedron, and even something as dull as a cube is something I can get behind. And so, naturally, I wondered: is there a periodic table of polyhedra? And the answer is “not exactly”. But there’s something pretty close

## Ask Uncle Colin: The Timeless SUVAT Equation

Dear Uncle Colin, I can derive the timeless SUVAT equation $v^2 = u^2 + 2as$, but I can’t intuitively see where it comes from. Any clues? - Everyone Needs Explanations, Really Get Yours Hi, ENERGY, and thanks for your message! This is one that I never really picked up on