Posted in ninja maths

A few months ago, @preshtalwalkar at Mind Your Decisions showed off how he'd advise someone to work out $43 \times 67$ using one of my favourite tricks, the difference of two squares. In fact, that's how I'd have approached the question at first, too: the two numbers are 12 either

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Posted in ask uncle colin, fractions

Ask Uncle Colin is a chance to ask your burning, possibly embarrassing, maths questions -- and to show off your skills at coming up with clever acronyms. Send your questions to colin@flyingcoloursmaths.co.uk and Uncle Colin will do what he can. Dear Uncle Colin, I'm having trouble cancelling fractions -- in

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Posted in modelling

The estimable Barney Maunder-Taylor asked at MathsJam: How come the inverse square law leads to elliptical orbits and equal area swept in equal time? I only know the answer to one of those questions. The differential equations for the inverse square laws work out to be: $\diffn{2}{r}{t} - r \left

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Posted in ask uncle colin, core 3, trigonometry

Ask Uncle Colin is a chance to ask your burning, possibly embarrassing, maths questions -- and to show off your skills at coming up with clever acronyms. Send your questions to colin@flyingcoloursmaths.co.uk and Uncle Colin will do what he can. Dear Uncle Colin, I've been given a trigonometry problem I

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Posted in ninja maths, trigonometry

"$\sin(15º)$," said the GCSE student, and the Mathematical Ninja -- recognising that the qualification recognised idiotic angle measures -- let it slide. "0.2588", he muttered, under his breath, knowing full well that the exact answer -- $\frac{\sqrt{6} - \sqrt{2}}{4}$ -- would get him a blank stare. He sighed the sigh

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Posted in podcasts

In this month's exciting instalment of Wrong, But Useful, @reflectivemaths and @icecolbeveridge discuss: The number of the podcast: 36.16 seconds, the current world record for sorting a pack of cards Dave is reading The Number Devil: A Mathematical Adventure -- and asks what happens if you colour in the multiples

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Posted in algebra, ask uncle colin, core 1, quadratics

Ask Uncle Colin is a chance to ask your burning, possibly embarrassing, maths questions -- and to show off your skills at coming up with clever acronyms. Send your questions to colin@flyingcoloursmaths.co.uk and Uncle Colin will do what he can. Dear Uncle Colin, How do I solve $3x^{\frac{2}{3}} + x^{\frac{1}{3}}-2

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Posted in fractions, ninja maths

A redditor asks: How would I find a good rational approximation to something like $\log_{10}(7)$? The Mathematical Ninja mutters 0.85 under his breath, as a matter of course, reasoning that $\log_{10}(7) \approx \log_{10}\left(\sqrt{ \frac {10^2 }{2} } \right)$, although my calculator says 0.845098, so he's off by about 0.6%. However,

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Posted in ask uncle colin, further pure 1, matrices

Ask Uncle Colin is a chance to ask your burning, possibly embarrassing, maths questions -- and to show off your skills at coming up with clever acronyms. Send your questions to colin@flyingcoloursmaths.co.uk and Uncle Colin will do what he can. Dear Uncle Colin How can you look at a matrix

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Posted in calculus, circles, core 4, ninja maths, pirate maths

"Let me see that!" commanded the Mathematical Ninja, looking at one of the Mathematical Pirate's blog posts. "That's... but that's..." "It's not wrong!" said the Mathematical Pirate, smugly. "It just works!" "But you're presenting it as magic, not as maths." The Mathematical Pirate nodded eagerly. "Lovely magic! How does it

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