👤

1/1 ori 3 + 1/3 ori 5 + 1/5 ori 7 +..........1/n(n+2)= 8/17


Răspuns :

1/2·(1/1 - 1/3) + 1/2 ·(1/3 - 1/5) + 1/2 ·(1/5 - 1/7) +.......+ 1/2 ·[1/n - 1/(n+2)] = 1/2[ 1/1 - 1/(n+2)] = 1/2 ·(n+1)/(n+2) = 8/17
(n+1)/(n+2) = 16/17
17n + 17 = 16n + 32
n = 15