# September, 2013

## Cosines of small angles – Secrets of the Mathematical Ninja

"Where the hell have you been?" asked the student. The Mathematical Ninja raised an eyebrow into his well-tanned forehead. That, he didn't say, would be telling. The student sighed and sketched out a triangle. "I know that doesn't look like 2º," she said, to forestall any criticism. The Mathematical Ninja

Hey! By the time this goes live, I'll be in Germany, making final preparations to run the 40th BMW Berlin Marathon. I've been in training for the last six months, and who knows? Maybe I'll make it all the way around the 42,000 metre course. Mo Farah, eat your heart

## Wrong, But Useful: Episode 7

It's an awfully short episode of Wrong, But Useful, in which and I discuss: Colin's upcoming marathon efforts, which you can support by clicking here - bonus points for mathematically interesting sponsorships! Dave's son Reuben had his appendix removed, and Dave spent the time grumbling (justifiably) about parking and looking

## Review: Beating the Odds, by Rob Eastaway and John Haigh

I believe the version of this book I borrowed from the library may not be the most recent edition; it has been published under at least three different titles. As far as it goes, Beating the Odds: The Hidden Mathematics of Sport is great. It's a terrific starting point for

## TMTOWTDI: Subtraction

"There's more than one way to do it." - Perl programming motto One of my few regrets about writing maths books is that I usually only get to show one way of doing things - and that gives the impression that I believe Method X is absolutely, no questions, the

## Maths: You’ve got it all wrong

A guest post, today, from someone who's almost as angry as the Mathematical Ninja. Bletchley Park's Education Officer Tom Briggs is mad as hell, and he's not going to take it any more. I'm not a maths teacher any more1 but I still find myself having those same old conversations...

## Two trains and a fly

There's a classic maths puzzle that goes something like this: Two trains start 20 miles apart, and travel towards each other at 10 miles per hour. Just as they start, a fly takes off from the front of one train, flies at 15mph directly to the other, turns around, flies

## Sorting a list on the fly

I was writing a sort of revision sheet the other day, and I'd written the questions in a sensible order, but wanted to shuffle them randomly so that students wouldn't know what's coming next. This is not the kind of thing Microsoft Word was built for. I decided to start

## Billy Beane: Lives of the Mathematical Ninja

Unusually for a Mathematical Ninja, Billy Beane isn't a mathematician. Nor is he dead. He's a baseball manager. Now, I don't know one end of a baseball stick from another, so this will be strewn with errors: one thing I do know, thought, is that if I was a baseball

## The Mathematical Pirate’s guide to the Chain Rule

"Yarr!" said the Mathematical Pirate, chopping his way through the piles of papers strewn around the classroom. The student looked unimpressed. "How do you differentiate $y = \sec^2(3x)$?" she asked. The Mathematical Ninja would have discerned that she'd just read the question without trying to solve it, but the Mathematical