# Browsing category algebra

## The easy way to factorise nasty quadratics

Until about three years ago, I had literally no idea how to factorise nasty quadratics. I would turn straight to the quadratic formula, go bing bang boom and say 'there, job done.' This was a very effective short-cut - I got a long way with my ignorance - but I'm

## The smart way to do the binomial expansion (Part II)

This is a follow-up to Monday's post about the smart way to do the binomial expansion. In this one, we're going to look at how to do C4 binomial expansions - ones with crazy powers like $-3$ or $\frac{3}{2}$. This bit is very important: you should COMPLETELY ignore the formula

## The smart way to do the binomial expansion (Part 1)

Ah, the binomial expansion. The scourge of my A-level: the sum that was always wider than the paper, and always had one more minus sign than I'd allowed for. A crazy, pointless exercise in arithmetic, if you ask me, only really useful for finding square roots in your head (of

## The maths of the decathlon

While I'm quite steadfastly refusing to be swept along with either Olympics fever or anti-games grumbling, I stumbled across the Wikipedia page for the decathlon in a moment of nostalgia for my 1980s childhood tapping the keys of the ZX Spectrum - a system that was kind of like an

## Reverse engineering your prime birthday

If you follow the great big geeks on twitter - and , I'm looking at you - you'll have seen bits and pieces of discussion about prime birthdays. How to find your next prime birthday It's your prime birthday if you've been alive for a number of days that happens

## The ‘Dating Rule’

Two things: the somewhat random-looking picture above is from The Moon Is Blue, a 1953 film that's the first known reference to the 'dating rule' discussed here. Secondly, I don't make any judgement about the validity of the 'dating rule' - you might find it a useful rule of thumb