Math Quiz #1

Without using a calculator or a computer,determine which of the square root of 2 and cubic root of 3 is the greater number ,which of the cubic root of 3 and the fifth root of 5 is the greater one and as bonus question  which of the 3 roots is the larger number?

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Un peu de logique?

Pour vous stimuler les méninges je vous propose un petit exercice:

Imaginez un voyageur qui débarque à la nuit tombante dans l’île aux Contraires. Cette île a la particularité d’être divisée en deux :d’un côté habitent les Vertueux ,de l’autre les Adrets ,vagues descendants du tristement célèbre baron des Adrets. .Les Adrets non seulement détroussent les voyageurs égarés dans leur partie de l île mais quand on leur pose une question, ils mentent toujours. Les Vertueux, par contre, disent toujours la vérité. Malheureusement pour notre voyageur ,rien dans leur apparence ne distingue les Adrets des Vertueux. Ayant pour objectif de se rendre chez les Vertueux,il arrive à un croisement au sortir du port ,il ne sait pas s’il lui faut aller à droite ou à gauche, sachant que s’il se trompe il risque d’être détroussé ou pire. Il hésite, perplexe et craintif, quand il voit un passant.

Ne pouvant déterminer si ce passant est un Adret ou un Vertueux, et donc si le passant lui dira ou non la vérité, quelle est la question que notre voyageur peut lui poser pour être sûr ,quelle que soit l’identité du passant ,que la réponse le mettra sur le chemin des Vertueux?

Envoyez-moi vos solutions en postant un commentaire et dans une semaine la réponse sera publiée.

Discrimination in the animal kingdom

Praying mantises are known to devour their mates after having enjoyed the poor males’ sexual prowess [1].This behavior is not unique in nature: female spiders are also known to feast on their sexual partners especially when the males are smaller than the female [2] and now scientists have discovered a similar behavior in female rattlesnakes [3] shortly after giving birth, apparently out of a need to replenish her energy and become reproductive again.

Are the males of the animal kingdom always the victims of their mates? Not quite, according to research published in the very learned American Naturalist [4],certain male fishes become cannibals when they suspect they have been cuckolded and the off springs are not really theirs.

Assuredly, no one could find parallels between the human and animal behaviors!


[1] cf. University of Chicago Press Journals. « Male Praying Mantids Prefer Not To Be Victims Of Sexual Cannibalism. » ScienceDaily 27 July 2006. 22 February 2009 <http://www.sciencedaily.com/releases/2006/07/060726183753.htm#&gt;.

[2] University of Chicago Press Journals. « Female Spiders Eat Small Males When They Mate. » ScienceDaily 11 September 2008. 22 February 2009 <http://www.sciencedaily.com/releases/2008/09/080910165846.htm&gt;.

[3] Plataforma SINC. « Cannibalism Among Rattlesnakes Helps Females To Recover After Birth. » ScienceDaily 22 February 2009. 22 February 2009 <http://www.sciencedaily.com/releases/2009/02/090219095533.htm&gt;.

[4] Suzanne M. Gray, Lawrence M. Dill, and Jeffrey S. McKinnon, « Cuckoldry incites cannibalism: male fish turn to cannibalism when perceived certainty of paternity decreases. » The American Naturalist: February 2007.

Sharks, hemlines and the economy

According to traditional hemline theory ,as hemlines go up so does the market-remember the Roaring Twenties when the flappers’ skirts got noticeably shorter, or the Swinging Sixties heralding the miniskirt and a long up cycle in the market ,and as hemlines go down so does the market -as we witnessed in the 30s and 40s.

Now, according to  George Burgess, ichthyologist and director of the International Shark Attack File,at the University of Florida we can say ,with science on our side,that as shark attacks go down so does the level of economic activity .Perhaps the trend might be reversed if our ladies were to lift their skirts at the sharks!For more information, see: University of Florida. « Shark Attacks Decline Worldwide In Midst Of Economic Recession. » ScienceDaily 20 February 2009. 20 February 2009 <http://www.sciencedaily.com/releases/2009/02/090219111000.htm#>.