# Carnival of Mathematics, 110

It’s the 110th Carnival of Mathematics - and I fear I’ve drawn the short straw. I suppose, as the numbers climb higher, there are fewer interesting facts to go around.

However, a few that jump out:

- it gives the minimal value (-5) of the Merten’s function ( http://en.wikipedia.org/wiki/Mertens_function )
- it’s the sum of three consecutive squares ($5^2 + 6^2 + 7^2$)
- it’s the frequency, in hertz, of an A two octaves below a typical tuning fork
- it is - the Mathematical Ninja reminds me, just below $\left(\frac{21}{2}\right)^2$, and not all that far from the inverse cosine of -1/3 (in degrees)
- it’s the binary representation of 6, which is a much more interesting number
- 110 years ago this year, Jacobi was born.

It’s also how many percent I’m going to give to putting this month’s links into some sort of sensible order, and what Joe Roberts must have done through Michigan County that night.

### How we feel about maths

Just how rubbish a number is 110? It’s the world’s least favourite number, according to Alex Bellos. This video (from Egan) shows us why everyone loves seven - although ‘everyone’ doesn’t include Sheldon, of course. Math 110 is one of the courses mentioned in How I Slayed The Mathematical Beast-Monster by Karla Gabruch, also via Egan - a heartbreaking story of how a bright-but-not-fast girl’s mathematical confidence was destroyed - and how she’s worked to tame the maths beast.

Serious mathematicians, of course, don’t try to tame the maths beast; no, we work out ways to abstract it into fanglessness and reduce it to a previously-solved problem. Tanya Khovanova encapsulates this perfectly in this celebration of laziness. The kind of rote memorisation that reduced Karla to tears is taken to task by Mr Koh, here - it always stuns me when students prefer to learn twelve formulas rather than think things through. Cav has a justified pop at EdExcel over their ‘real-life maths’ problems that are no such things; (I still think Kate the Photographer was framed).

On a much more positive note, Shecky points us at how ‘mathodist pastor’ Keith Devlin got out of the forest and began to see how maths fit together - a lovely image, and not a beast in sight! There is no mathematical beast more fearsome than Thony Christie with a correction to make; here, he takes on some of the attributions on Ian Stewart’s 17 Equations.

### Puzzles

Cav’s also sent us a collection of puzzle-related posts:

- The semicircle puzzle
- A fractional puzzle
- A fantastic puzzle
- Another fantastic puzzle
- A fiendishly hard puzzle

Adam Goucher, meanwhile, has been tackling some of the unsolved problems at Math Exchange, and stumbled into the murky world of golygons and golyhedra. While we’re on the subject of unsolved problems, I think Alfredo Salvador García is claiming here to have proved the Goldbach conjecture - I may have misunderstood, but it’s too late at night for me to be trying to find flaws in proofs.

### Cool maths nuggets

It wouldn’t be a Carnival without some cool maths nuggets. Let’s start with a hearty welcome back to blogging, and Carnival-land, to Javier Pazos, the Science Pundit, with a post on 2048 and the golden ratio. William Wu gives us a nice, intuitive (although informal) proof of the Maclaurin Series ((discovered by Taylor)). Jamie has been exploring parabolas with his kids:

… and finally, to take us back to Alex Bellos, Richard Snape has a look at the chances of lottery failure - I’ve covered something similar in the past here.

* Alex’s latest book, Alex Through the Looking Glass, is out now. I’ve mysteriously not been sent a review copy.