Double Maths First Thing is what the internet used to be like before billionaires bought it.

Hello! My name is Colin and I am a mathematician on a mission to share joy and delight in maths.

I’m writing this in a rush, so it’s just a list of links this week. Soz like. I’m rushed because I’ve just got back from my local MathsJam, where we had an unprecedented 11 people. Decimal, although we often struggle to reach that in binary. We had to use several tables and there were arguments over the scissors.

Links

There’s a bit in Surely You’re Joking, Mr Feynman where he talks about a technique for differentiating under the integral sign. For all that Feynman is a… problematic character, there’s some neat maths there — and Leo Goldmakher has a lovely paper explaining it

Talking of lovely things, a redditor pointed out that you can approximate the Gaussian integral by \( \sin⁡(\sin⁡(x))\) for quite a decent range of \(x\) values.

Also via reddit, I’ve been introduced to sinh-tanh quadrature, a numerical integration technique with really nice properties (endpoints can be ridiculous! you can reuse your previous work if you find you need a better approximation! it’s just neat!)

From the glorious to the horrifying: here’s Matt Parker explaining a regex that finds primes. Now I have infinitely many problems.

And somewhere in between is an article from 1985 about the elegant maths of the double-entry book-keeping method.

Lastly, there’s a Finite Group livestream on Friday lunchtime about combinatoric games — you’ll need to be a paid member if you want to watch it, but being part of the community is easily worth the price of a fancy coffee a month.

That’s all I’ve got this week! In the meantime, if you have friends and/or colleagues who would enjoy Double Maths First Thing, do send them the link to sign up — they’ll be very welcome here.

If you’ve missed the previous issues of DMFT or — somehow — this one, you can find the archive courtesy of my dear friends at the Aperiodical.

Meanwhile, if there’s something I should know about, you can find me on Mathstodon as @icecolbeveridge, or at my personal website. You can also just reply to this email if there’s something you want to tell me.

Until next time,

C