Question

Sa se determine n∈N pentru care f(0) + f(1) + .... f(n+1) = 131071

Answer 1

folosesti termenul general $a_{n}= a_{1} q^{n-1}$   q=ratia

q=$\frac{ a_{n} }{ a_{n-1} }$ => q=2
Sn=$\frac{ a_{1}(1- q^{n}) }{1-q}$
Sn=-2+$2^{n+1}$ =>
131070=$2^{n+1}$-2 => 2*$2^{n}$=131072
$2^{n}=65536$