September 7th, 2006, 7:23 pm
THis one is quite a hard one :1-what is the probability that 2 intergers have no common diviser except 1 ( they are prime to one another, like 4 and 15).(hint : you have to use the function zeta (not sure of the name) to write the answer, ie f x = sum 1/k^x k from 1 to inf, x>1)Another one as hard as the one before :Proove that when you take a matrix of normal gaussian number of size n*n and you look at the repartition function of its eigenvalues, you obtain a semi circle.Good luck !