# January, 2019

## Ask Uncle Colin: A dangling rope

A Hanging Rope Dear Uncle Colin, I’m designing a small cathedral and have an 80-metre long rope I want to hang between two vertical poles. The poles are both 50 metres high, and I want the lowest point on the rope to be 20 metres above the ground. How far

## Wrong, But Useful: Episode 63

In this month’s installment of Wrong, But Useful, Dave and I are joined by @honeypisquared, who is Lucy Rycroft-Smith in real life. We discuss: Mathematical board games, including The Mind Camel Cup Qwinto Number of the podcast: Lucy doesn’t like numbers so we don’t have one. Does your collection of

## What I learnt from a STEP Speedrun

I’ve been doing some work on STEP recently – maths exams used mainly for entrance at Cambridge and Warwick, who want some way to differentiate between very good A-level candidates. When I was in Year 13, I had an interview – in fact, two interviews – at Cambridge; at one

## Ask Uncle Colin: Integrating $\sec$ and $\cosec$

Dear Uncle Colin, I keep forgetting how to integrate $\sec(x)$ and $\cosec(x)$. Do you have any tips? – Literally Nothing Memorable Or Distinctive Hi, LNMOD, and thanks for your message! Integrating $\sec(x)$ and $\cosec(x)$ relies on a trick, and one the average mathematician probably wouldn’t come up with without a

## The Dictionary of Mathematical Eponymy: Ackermann’s function

For 2019, I’m trying an experiment: every couple of weeks, writing a post about a mathematical object that a) I don’t know much about and b) is named after somebody. These posts are a trial run – let me know how you find them! The chief use of the Ackermann

## Ask Uncle Colin: A Strange Simultaneous Equation

Dear Uncle Colin, I have the simultaneous equations $3x^2 – 3y = 0$ and $3y^2 – 3x = 0$. I’ve worked out that $x^2 = y$ and $y^2 = x$, but then I’m stuck! – My Expertise Relatedto1 Simultaneous Equations? Not Nearly Enough! Hi, MERSENNE, and thanks for your message!