# January, 2012

## Questions with only one answer

There are many questions with only one answer. Or at least, one sensible answer. If someone asks you “Are you dead?”, the only possible answer you can give is “no”. “Does my bum look big in this?” “Of course not, dear, it looks lovely”. And if you say “Is there

## Free for all Friday

Well… it’s not really a free-for-all Friday as I’m on a train to Bristol, but you can still leave me questions here and I’ll respond when I’m back in front of a computer. Any A-level maths topics – including Further Maths – you’re struggling with, I’ll be happy to help

## The Line of Best Fit (Linear Regression)

Have a look at this picture. What do you notice? “It’s a straight line, Colin!” Very good. You could get a ruler out and draw a straight line through the points. Why would you bother doing such a thing? Well, the idea is that if you can model a data

## How to do calculus with $a^x$

Every time you’re asked to differentiate $a^x$ and you say $xa^{x-1}$, a kitten dies. A kitten that had been raised lovingly by an orphan, her only friend in the whole wide word – DEAD, just because you couldn’t be bothered to learn how to do calculus properly. I hope the

## Free for all Friday

It’s Friday, which means… It’s free for all Friday time! Any questions you’ve got, about maths or anything else, pop them in the comments. I’m in the middle of the deadline doldrums (the next Dummies book won’t write itself, you know!) but I’ll pop in once in a while to

## Why radians rock (and degrees don’t)

If I could wave a magic wand and overhaul just one thing to make the world a better place, I’d have a tough choice. Would I get rid of the QWERTY keyboard in favour of a more sensible layout? Would I make the English language fonetik? Would I take maths

## How to do… R-sin-alpha questions

There’s a very typical question in C3 papers that looks something like: “Express $3 \sin (x) + 5 \cos (x)$ in the form $R \sin (x + \alpha)$.” (Sometimes it’s a different trig function, or it may have a minus sign in it, but the same principle works for any

## Free-for-all Friday

It’s C1 day (and C2 for many)! I hope it’s gone well if you were sitting it today. Anything that bothered you about the paper? It’s your chance to pick my brain about whatever’s on your mind about maths. Got a question you’ve been struggling with? Got a topic you

## Aces in the pack

Today’s big question is about poker. For some reason, statistics books shy away from gambling, reasoning that it’s somehow harmful or evil. It’s true, it can be addictive (although so can, for instance, using the computer or reading books) but it’s actually the whole reason statistics exists. (This Italian lad,

## Core 1 graphs: all you need to know

Part I: Basic shapes of Core 1 graphs There are a handful of basic shapes of graphs you need to know about for C1, namely: – reciprocal graphs ($y = \frac{1}{x}$) – reciprocal-square graphs ($y = \frac{1}{x^2}$) – straight line graphs ($y = x$) – you know this one, right?

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##### Where do you teach?

I teach in my home in Abbotsbury Road, Weymouth.

It's a 15-minute walk from Weymouth station, and it's on bus routes 3, 8 and X53. On-road parking is available nearby.