Calculators

Friday 25 March 2005 at 2:40 pm | In Articles | 3 Comments

eon has brought my attention to Tall, Dark & Mysterious’s post about the use and abuse of graphical calculators which is worth reading.

It mentions the use of calculators on mobile phones etc, but I don’t allow their use in maths classes because they give the wrong answer (try 1+2 \times 3 on them or on the Windows standard calculator and you’ll see what I mean).

The new A level syllabuses don’t distinguish between scientific and graphical calculators, but both are banned from the first Pure Maths module. It will be fascinating to see how students cope with this.

My Norwegian students all have graphical calculators (mainly Casio which I find difficult to use compared with Texas, though I like Casio’s scientific calculators) and the only way they are able to solve quadratic equations is to use the calculator, even if the quadratic factorises easily.

Other students, being students, don’t always bring calculators even when they need them. So when they have to solve \sin\left(3x+45^{\circ}\right)=0.7,\  -90^{\circ} \leq x \leq 90^{\circ} I am very tempted to give them old-fashioned four-figure tables (which you can still buy!) but instead I give them an old scientific calculator. On those, to find \sin 30, you have to type 30 \sin which so flummoxes them that they don’t forget to bring their own calculator again :D

Online Mathematics Site

Monday 21 March 2005 at 6:17 pm | In Articles | Post Comment

Computer algebra packages have developed dramatically over the years, Mathematica probably being the most well-known, though there are plenty of others – see for example the list at Wikipedia.

For those who just need to work out a problem there are also online resources. One well-known one is Integrator, which as its name suggests, will give indefinite integrals. It is important though to use the correct syntax required by Mathematica which powers the site, otherwise Integrator tells you \int \cos(3x)\;dx=\dfrac{3\cos x^2}{2} :-? instead of the correct \int \text{Cos}[3x]\;dx=\dfrac{1}{3}\text{Sin}[3x].

However, I have just come across QuickMath which, although it is also powered by Mathematica, allows a more friendly input using cos(3x) rather than Cos[3x]

The site says it will do

    Algebra
    -Expand
    -Factor
    -Simplify
    -Cancel
    -Partial Fractions
    -Join Fractions
    Equations
    -Solve
    -Plot
    -Quadratics

    Inequalities
    -Solve
    -Plot

    Calculus
    -Differentiate
    -Integrate

    Matrices
    -Arithmetic
    -Inverse
    -Determinant

    Numbers
    -Percentages
    -Scientific notation

QuickMath says it has been going in various forms since 1998. How come I haven’t seen it before? It is certainly worth investigating and it will be interesting to hear how users get on with it. Are there similar sites out there?

Strange phrase

Sunday 20 March 2005 at 5:33 pm | In Articles | 2 Comments

Heard on BBC Radio 4 news last night:

    If Wales hadn’t beaten Ireland in the rugby match then it’s mathematically possible that France could have won the Grand Slam

This use of the phrase mathematically possible to mean a small probability is not uncommon, particularly in sport. And it’s not confined to the UK as Mathematically Possible shows. It would be interesting to find out how this phrase came to have this strange meaning.

LambertW

Friday 4 March 2005 at 3:09 pm | In Articles | Post Comment

Last year I wrote a piece about the LambertW function. Now the American Scientist has an excellent introductory article to this function here.

The article mentions a LambertW poster you can find here.

Mathematics is Front Page News!

Wednesday 2 March 2005 at 5:59 pm | In Articles | Post Comment

It’s not often that mathematics gets onto the front page of a national newspaper but today the discovery of the latest prime has pride of place on the front page of the Guardian together with a colourful picture of some of the digits of this prime number. You can see the front page here (the story is the middle column) and read the story itself here.

Full details are at The Great Internet Mersenne Prime Search (GIMPS)

Powered by WordPress with Pool theme design by Borja Fernandez.
Entries and comments feeds. Valid XHTML and CSS. ^Top^