Posted in gcse, trigonometry

My dad tells me that, above the blackboard in his 1960s Scottish high school, was a banner with the letters ‘SOH CAH TOA’ written out on it. Any questions about the banner were brushed off with a smile and ‘you’re not old enough to learn about SOH CAH TOA yet.”

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Posted in ranting

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

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Posted in 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

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Posted in statistics

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

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Posted in calculus, core 3, logarithms

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

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Posted in 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

Read More →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

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Posted in core 3, trigonometry

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

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Posted in 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

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Posted in probability, statistics

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,

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