Latest Prime Found

Wednesday 28 December 2005 at 2:17 pm | In Articles | 3 Comments

Using 700 computers a new Mersenne prime has been found. It is 2^{30,402,457}-1 and has 9,152,052 digits. The $100,000 prize for a prime with more than 10 million digits is still up for grabs!

More at ZDNet News and GIMPS.

Problem

Saturday 10 December 2005 at 8:32 pm | In Articles | 4 Comments

There was a nice little problem posted on S.O.S. Mathematics CyberBoard which comes from an International Mathematics Tournament of Towns question:

    The least common multiple of positive integers a,b,c and d is equal to a+b+c+d. Prove that the product abcd is divisible by at least one of 3 and 5.

If you need a hint you’ll find one on the AoPS Math Forum

Singapore

Thursday 8 December 2005 at 10:25 pm | In Articles | Post Comment

eon gives a brief but fascinating look into Science and Maths in Singapore. Perhaps eon can be encouraged to expand on this.

Gratuitous Mathematics

Thursday 1 December 2005 at 7:11 pm | In Articles | 4 Comments
    \displaymath q_x=1-e^{-\int^1_0\mu_{x+t}}\:dt
    The meaning of life? (Not quite but this formula will tell you much of it you have left*)

That’s how the Guardian today publicised its article on life expectancy. It then attempted to ‘explain’ the formula with a tiny note saying *Details overleaf. These ‘details’ were:

    The force of mortality at age x is defined as: \mu=GM(r,s), with parameters a_1,\dots,a_r and b_1,\dots,b_r fitted by maximum likelihood. For example, GM(2,3)=a_1+a_2 t+e^{b_1+b_2 t+ b_3 (t^2-1)} where t=\frac{(x-70)}{50}. The the equation above shows the probability that someone aged x will die within one year. Still puzzled? See page 8.

On page 8 is the article So, how long have we got? which sheds no light on the formula; it doesn’t even mention it.

So why was this formula there? To make the journalist or the paper look clever? Who knows. But it certainly is completely useless even to mathematicians. The example just makes the whole thing even more obscure. Wouldn’t it be nice to have more mathematically trained journalists who wouldn’t just show off but instead make things clearer?

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