19.1.2.5 Convergence in Metric Spaces

Condition: whether the sequence \ (\ left \ {x_ {n} \ right) \), \ (x_ {n} = \ left (1, \ frac {1} {\ sqrt {2}}, \ ldots, \ frac {1} {\ sqrt {n}, 0, \ ldots \ right) \) in space \ (l_ {3} \)?