The probability that an athlete will not win any of the three races is 1/4.
If the athlete runs in all the races, what is the probability that the athlete will win:
(I) only the second race:
(ii) all the three races
(iii) only two of the races?
Soient a et b deux re^ els. Pour tout n ∈ N on pose
u_n =(√n)+a(√(n+1))+b(√(n+2)).
1. Ve^ rifier que la suite (u_n ) tend vers 0 si et seulement si a+b=−1.
2. De^ terminer a et b pour que la se^ rie Σu_n soit convergente.