Question

Fie a∈R astfel incat |a|≤$\frac{1}{n}$ oricare ar fi n∈N.Aratati ca a=0.

Answer 1

lal≤1/n<=.>
-1/n≤a≤1/n
-1/n→0  cand  n→∞
1/n→0  cand n→∞  =>
0≤a≤0 =>  a=0