My MS221 books finally arrived on Wednesday, and it wasn’t until I’d opened the package that I realised I was supposed to use the copy of Mathcad that I’d been sent for MST121 a couple of years ago – if I’d realised sooner, I could have been installed it days ago! I had a brief panic when the installation wizard asked for a password, but thankfully the OU Computing FAQ page contains a valid password (this is the link, which I presume will only work if you’re currently enrolled on MS221).

So with that little crisis out of the way, I’ve been working through Section 3 of MS221 Chapter A1, which is about finding closed forms for linear second-order recurrence sequences. In particular we looked at Binet’s formula:

Binets formula, a closed form for Fibonacci numbers

Binet's formula, a closed form for Fibonacci numbers

So now I can impress and astound Alex by quickly calculating any term of the Fibonacci number sequence he likes!

The activities in this section were lots of fun, but there were a few bits where I suffered from being clumsy and out of practice with various algebraic techniques. In particular, I couldn’t remember how to solve simultaneous equations, so I had a look at the very helpful Simultaneous Linear Equations leaflet from, which sorted the problem out fairly quickly.

It’s embarrassing not to remember stuff like that, but I suppose it’s to be expected when you don’t practice a certain technique for a long time. Which is a good reason to keep doing maths courses – or at least, to keep doing maths problems, even if they’re not in the context of a formal qualification or course; I’m sure if ever I run out of money for OU course fees, I’ll end up haunting the educational textbook section of my local library every evening and weekend!