# The Flying Colours Maths Blog: Latest posts

## Ask Uncle Colin: An emergency limit!

Dear Uncle Colin Help! An emergency has arisen and my L'Hôpital's Rule is out of order -- but I still need to find $\lim_{x \to 0_+} \frac{\ln(x)}{\cot(x)}$! This is not a drill! -- Help! Inexplicable Limitations Bring Everyone Ridiculous Trouble Don't panic, HILBERT! Don't panic. Now, for the benefit of

## Review: The Ideas Factory, by Jon Gertner

It was an incredible idea: gather together as many really smart people as possible and set them to work on discovering the essential nature of things. At least, it was an incredible idea around the time of Pythagoras, or the time of the House of Wisdom, or any time anyone

## Matrix Determinants — TMTOWTDI

Oh, the days -- weeks, even -- of my university life I spent working out the determinants of matrices. The 3×3 version was the main culprit, of course, usually needing to be split down into three smaller determinants, and usually requiring a sign change in one or two that I'd

## Ask Uncle Colin: Missing Numbers

Dear Uncle Colin, My teacher recently challenged me to tackle the missing numbers problem below and I don't know where to start! It's driving me to disgust with the whole number system. Crazy Old Numbers, Wacky And Yucky #Edtech and gimmicks won't help students solve this, but considering the nature

## Review: Birth of a Theorem, by Cédric Villani

It's a best-seller in France, apparently: the wild-haired but immaculately-dressed Fields Medallist's story of how he and his colleague solved the Landau damping problem. But therein lies my difficulty with it: I don't know about, or especially care about, the Landau damping problem. It's a McGuffin: it might as well

## Wrong, But Useful, Episode 30: MathsJam Special

In a departure from the norm, Wrong But Useful tries its first panel game. In a completely original format, our intrepid podcasters trade lies in a panel game entitled Spoof My Proof. On Colin's team: @christianp (Christian Lawson-Perfect) and @dragon_dodo (Dominika Vasilkova) On Dave's team: @realityminus3 (Elizabeth A. Williams) and

## Ask Uncle Colin: Random Points on a Sphere

Dear Uncle Colin, In one of Randall Munroe's What If? articles he says that the maths of finding a random point on a sphere is a bit hairy. Can't you just pick a random latitude and longitude? -- Surely Places Have Equal Random Expectations You would think so, wouldn't you,

## Review: The Numbers Game, by Chris Anderson and David Sally

"'The book that could change football for ever' -- The Times," screams the garish orange front cover. Noted football experts Malcolm Gladwell and Billy Beane shower it with praise. Apparently everything I know about football is wrong. Despite all of the dubious hype, The Numbers Game: Why Everything You Know

## How the Mathematical Pirate works out the high times tables

"Arr!" said the Mathematical Pirate. "Pieces of eight!" said the Mathematical Pirate's parrot. "How many pieces of eight?" "Seven!" "That'll be... seventy and ten minus twenty and four, making fifty and six!" "Who's a clever boy?" asked the parrot. "Awk!" --- The Mathematical Pirate is, indeed, a clever boy. He's

## Ask Uncle Colin: Multiplying negatives

Dear Uncle Colin, I'm finding it hard to understand why, when you multiply two negative numbers together, you get a positive number. I accept that it's true, but I was brought up to believe that two wrongs don't make a right. -- Positive Equals A Negative Otherwise? There is a