## Archive for May, 2011

### How to find the equation of a quadratic function from its graph :: squareCircleZ

Wednesday, May 18th, 2011

Murray Bourne of squareCircleZ has posted on ‘How to find the equation of a quadratic function from its graph‘. This is indeed the type of discussion and exercise that we need to see more of.  Not only does it promote a deeper understanding of the mathematics than the reverse but it is also relevant to more practical applications. Occasionally we do come up with a formula and want to see what it looks like but, especially when it comes to specific examples as opposed to general patterns, it is more often that we have data and want to find or verify a formula.  One of the activities in my own “Blue Meanies” game (at http://qpr.ca/math/applets/meanies/ )asks students to “guess” the equation of a parabola through three points by imagining the curve and using its geometry (in various ways) to determine the equation. Of course in such “modelling” problems, with limited data there will be many possible model types that can be used, and there is an interesting interplay between fitting with a particular class of functions (eg polynomial or exponential) and giving reasons why one or other such class might be more appropriate in a given situation.

Friday, May 13th, 2011

Howard Knopf doesn’t like the idea of extending the tax (or calling it one).

I didn’t like having to pay a tax, or “levy”, on the CDs I bought years ago to store photos and backup my HD, but I don’t see any difference between that bit of theft and this one. In fact, although I resent the presumption that the tax, or “levy”, is a fee for some service that I have no intention of using, I can live with the idea of a tax on media being used to support creative activities if that is the collective will of the nation.

Just don’t call it a “levy”, and interpret it as a fee for service, unless

(a)it entitles me to fill it with unlimited personal use copies of any works that I do buy, and

(b)there is some provision for levy-free media which are precluded from being used for copyright material (like the coloured tax-free fuel that is available in some places for farmers).

### Time for a Change

Tuesday, May 3rd, 2011

OK today must be the start of a four year campaign to reach agreement between the NDP, Greens, and remaining Liberals to:

1. Support an electoral reform which will provide for proportional representation – NOT based on party lists but on something more democratic like STV or some other preferential balloting system
2. Educate the Canadian public as to the acceptability, efficiency, and desirability of “coalition” governments – even (or perhaps especially) when not including the party which happens to have the most seats in parliament
3. Commit to endorsing strategic voting in the next Federal Election in order to achieve these ends

### The Escape of Osama Bin Laden

Tuesday, May 3rd, 2011

In retrospect it is obvious that the mission had no hope of success. Obviously anyone with the resources available to Osama bin Laden, when building a special-purpose hiding place, would have included an escape shaft from his apartment which led to a subterranean bomb shelter with a tunnel connecting it to the outside. At the first appearance of US helicopters OBL surely walked into the escape closet climbed down the shaft to his bomb shelter and by the time that the SEALs had fought their way up to his apartment he was well on the way down the half kilometer long tunnel from which he climbed out at an unknown location on the bank of a nearby gully or river. Good luck finding him now!

### Only Obama

Tuesday, May 3rd, 2011

Only Obama can deal with the financial collapse caused by  the right wing libertarian attitude towards proper regulation of financial institutions

Only Obama could persuade us that the Lion King was born in Hawaii

But Only Limbaugh could come up with the slogan which will should drive the great Democratic election sweep of 2012