Archive for November 2010

Mathematics: More than meets the eye!

November 13, 2010

The recent Transformers movies are some of the worst movies every made. They have nonsensical “plots”, direction that would ashame a moronic chimpanzee, and acting that would be boo-ed off the stage at a primary school.

Sort of appropriate then, that the nasty bit of algebra so far this year has the same name. I’m talking about Quadratic Transformations. We have already done the hard parts so far this year – you know how to complete the square, and you’ve practiced factorising until you are sick to death of it! You know the general solution to the quadratic equation formula (GSQEq – “G-Squeak”). Now we have to look at the discriminant:

But what are a, b and c? In the standard form of the quadratic equation, they are, respectively, the coefficients of the x squared term (a), the x term (b) and the constant (c). When you put these values into the discriminant formula (above), it tells you how many x-intercepts (sometimes called “roots” or “zeroes”) that particular quadratic expression has.

If the value of the discriminant is positive ( > 0), there will be two intercepts. If it is equal to zero, it will have one intercept. If it is less than zero, there will be no intercepts, as shown in the diagram above.

Here is a video – it’s not quite as bad as the latest transformers, but it is horrific in it’s own way:

Here are a sequence of videos that go into more detail; I recommend you check out the playlist, and decide which ones you need to watch.

Some links that may help you get your head around the concept (1, 2, 3, 4).

Remember that you must comment on posts if you want a good result for your ICT component.

ps. Another (older) post by me about quadratics and completing the square is at this link

See you in class.