Moonlighting agony uncle Professor Dirichlet answers your personal problems. Want the prof’s help? Send your problems to deardirichlet@chalkdustmagazine.com.
Dear Dirichlet,
I run one of the many pubs in my village, and I’ve been thinking about adding more potato options to the menu. The problem is, I think the landlord down the road has similar plans. If only one of us makes the change, it will undoubtedly attract more customers (everyone living here is a big fan of potatoes). But I’m worried that if we both do it, customers will think we’re in cahoots, and stop coming to either of our pubs. What do we do?!
— Christian D, Eynsham
Dirichlet says:
Ah, a classic case of the biz-owner’s dilemma. You have a few options here: you could apply some game theory and add some venison or pheasant to the menu. Ultimately, I think you’ll have to work with your neighbour to divvy up the menu items in a way that works for both of you: the Mash equilibrium.
Dear Dirichlet,
I was just calling my cousin in the 1960s and when I dialled the local switchboard, would you believe who picked up—the youthful radio broadcaster Tony Blackburn! Well, he said, he could certainly connect me to my cousin, he just had to put the audio plug into the circular socket marked with an elongated ‘S’ across it. I was eventually able to talk to my cousin but everything he said came across backwards. Was this to be expected or should I write a strongly worded letter to the General Post Office?
— Dame Judi Dench (not that one), Meald on the Weald
Dirichlet says:
What a palaver! Did you try placing the telephone receiver on the other side of your head? That should have fixed things—thinking of the markings on the audio jack, you must have connected to a-dj-\oint operator.
Dear Dirichlet,
To pass the time on our river cruise, my mother and I have struck up a friendship with a fellow passenger, and we’ve been playing a game of ‘guess the registration number’ whenever we pass a narrowboat. Usually this sort of harmless fun ends up with us winning about half the time, but our mysterious new friend is currently on a winning streak of 68–0. What gives?!
— River Cartwright, near Dudley
Dirichlet says:
I think I see the problem. You’ve been relying on the kindness of strangers, as well as the law of large numbers, to predict your overall winnings. What you’re actually dealing with is a conman—a bore of barge numbers who has memorised all the registration plates between Dudley and Wolverhampton. Try offering this gongoozler a different choice of pastime, but steer clear of any canal-themed betting. After all, the house(boat) always wins.
Dear Dirichlet,
A friend of mine has got a lovely kite-shaped bit of fabric, and wants to have a go at flying it. The problem is, we can’t work out how long to cut the bits of wood to give it some structure. They seem to be either too long, and then the kite is too heavy—or too short, and then it just collapses. Where are we going wrong?!
— Mr Banks, Cherry Tree Lane
Dirichlet says:
Ah, it’s kind of you to help out a friend. See if you can get them to measure the angles on the right, as well as the height of the bottom bit. Draw out some similar triangles, do a bit of trigonometry, and you’ll see the length you need is $1 + 2\tan\theta + \tan\theta\tan\phi$. Teamwork is the key here—after all, many tans make flight work.
Dear Dirichlet,
I’m organising a hen party for one of my friends. Any ideas for a good group costume?
— Katie, Ouseburn
Dirichlet says:
Kappa Demon Hunters. The Spice $\nabla\times$s. $\overline{\text{bie}}$. Six different members of Bourbaki. The Dallas Cowboys cheerleaders.
Heed Professor Dirichlet’s previous advice:
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