Mystery Math Idol Week of 12-17-07

Update: And the winner once again is...
Lynx!

Here's her contribution:

Jean le Rond d'Alembert is also famously known for incorrectly arguing in Croix ou Pile that the probability of a coin landing heads increased for every time that it came up tails. In gambling, the strategy of decreasing one's bet the more one wins and increasing one's bet the more one loses is therefore called the D'Alembert system. (WIkipedia)

From my reading of several biographies, it sonds as if he is another Cauchy - cantankerous, with many enemies and few friends.

My thoughts--
I've always associated D'Alembert with the Ratio Test for Infinite Series in Calculus but that's one of his minor accomplishments. He also solved the Wave Equation in Physics - not too shabby! On a personal note, his mom left him on the church steps when he was an infant. Later in life, when she wanted to reunite with him, he rejected her...
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Did you already notice I changed the image in the sidebar? Before I give a hint, I'll leave it up for another 12 hours as is.
Don't forget to email me at dmarain 'at' 'gee' mail dot com with your answer. As always, the name is not enough. Include a fascinating fact or anecdote about this famous individual and a reference or link that you used.

HAPPY HOLIDAYS!