I came across an interesting article the other day looking at the link between record breaking and the "harmonic series" $1 + \frac{1}{2} + \frac{1}{3} + \frac{1}{4} + \frac{1}{5} + ....$. If you went through a list of 100 random numbers, have a guess as to how often would you expect to break the record for the largest number so far? Let's take a simpler example. Here are 10 random numbers: 3, 8, 5, 7, 2, 5, 3, 9, 1, 7 Clearly the first number ...

# About: Ian Lucas

### Recent Posts by Ian Lucas

## Patterns in Pascal’s Triangle

One of the great joys in Maths is exploring something seemingly very simple and finding layers upon layers of complexity, and connections with other areas of Maths which at first sight appear to be totally separate. I'm sure you have come across Pascal's triangle; here it is: To create each new row, start and finish with 1, and then each number in between is formed by adding the two numbers immediately above. Pattern 1: One of the most obvious patterns is the ...

## Prepare Your Body and Your Mind for the Exams

This will probably be my last blog before you dive into the exams in May. I hope your revision has gone well: there's still time to go over more past papers to become as familiar as possible with the way the examiners ask questions. And don't forget that, in Maths exams, there's only one mark for the correct answer – all the other marks are for working and intermediate answers. So train yourself to write as much as you can ...

## Don’t Lose Marks Unnecessarily in Your Maths Exams

There is statistical evidence that 1 in 7 of you will lose marks which you shouldn't lose: in other words, there could be marks which you could easily gain, even if you can't answer a question, but what you put on paper didn't match the examiner's mark scheme. It's unlikely you're going to get 100%. Some questions you just can't see what to do; some you think you can do, but you get the wrong answer; or you run out of ...

## The Wine Glass and the Water Glass Puzzle

This is an old one but is a wonderful example of a puzzle with an unexpected, counter-intuitive solution. 'Two 50ml glasses are filled to the brim, one with wine and the other with water. A teaspoon (5ml) of water is transferred to the wine glass and thoroughly mixed in. Then a teaspoon of the mixture is transferred back to the water glass. Question: is there now more water in the wine, or wine in the water?' The more you think about it, ...

## Understanding Keywords in Mathematics Exams

Whether you are approaching your final exams, or you're at the stage of mid-course exams, you're probably beginning to put in some practice of past paper questions. Sometimes it isn't the maths which is hard, but understanding the language of the question; and each question will contain certain keywords which tell you how you should be tackling the question, and what you should be writing down. I can't emphasise enough how important it is to understand what, in the context ...

## Understanding the Chain Rule

Most students are first introduced to the chain rule when shown how to differentiate a function such as y = (3x - 2)5. The problem is that is tempting to try and fit all chain rule differentiations into that format, for example trying to differentiate e3x - 2 in the same way. What is the chain rule? It's a calculus formula with a wide range of uses, just one of which is differentiating a 'function of a function.' Quite simply, differentiation concerns the rate ...

## Straight Line Curves

It's a really relaxing bit of recreational mathematics (albeit with some serious theory behind it), creating beautiful curves just by drawing straight lines. I can only give a glimpse in this blog, but the possibilities are endless. If you're tempted to have a go, one word of caution: be as accurate as you can since the final result can be disappointing if you are careless, or work too fast. My first example is probably about the simplest you can do. I've ...

## Great Mathematicians 5: Al-Khwarizmi

Not heard of him? Born in 780 in what was then Persia, he became one of the learned men of the House of Wisdom in Baghdad. He lived to the age of 70 and, because of the breadth of his work in mathematics and the sciences, he must have been an amazing person to know. The House of Wisdom acquired and translated scientific and philosophical treatises, mainly from Greek, as well as publishing original research. Al-Khwarizmi's first major publication was The ...

## Some Mathematical Tips for the New Year

Happy New Year everybody! At this time last year I suggested some new year resolutions to help you in your studies. They are of course valid at all times, and if you didn't see them, then have a look now. This time I've got some tips which you might want to note down; they cover specific areas of the syllabus, although they aren't applicable to all of HL, SL, and Studies. Degrees or Radians? Well, it depends on what the question is asking you ...

### Recent Comments by Ian Lucas

- August 21, 2016 on Quadratic Factorisation