Politics Break & Completing The Square

well with the A Level results this week the annual debating on dumbing down continues. All I will say is that I can do A Level maths now and I couldn't in 1994: also that I can tell by the textbooks I have bought, borrowed and scrounged, that material has been moved, generally into higher modules over that time (complex numbers, trigonometry, series, and algebraic manipulation).

Having said that, you need, according to AQA's website, around 59/75 on C1 to get an A. This doesn't sound much but you can drop marks very easily and you don't have a lot of leeway.


I'll be signing up next month for C1 and S1 and possibly C2 in January so I can't really afford to make sarky comments about dumbing down to be honest. I don't fancy being bitten on the arse by an angry polynomial or a not very normal distribution.


By the way, for the benefit of one reader who googled completing the square "when it doesn't divide by two", it goes something like this.

3x² + 2x -1 = 0

3[x² + 2/3x] -1 = 0

3[(x+ 2/6)² - 4/36] - 1 = 0

3(x + 1/3)² -12/36 - 1 = 0


3(x + 1/3)² = 4/3

Then you start to solve the completed quadratic:

(x + 1/3)² = 4/9

x + 1/3 = +/- 2/3

x= 1/3
x= -1

You can check it alongside the quadratic equation if you like.

If you look at my fairly hasty working out you can see that whether the x² term divides by anything isn't the point: you simply take out the co-efficient from the x² term and divide the x term by it as well, as I've done here.

I will do more on completing the square soon but I wanted to see if I could answer that reader's query. I hope they have popped back to check!