Solution
= Solution
Take $a_n=n$. Every <subsequence> has the form $a_{n_k}=n_k$, with $n_k\ge k$, so it tends to positive infinity and cannot converge to a real number. Thus \b[this <sequence> has no convergent <subsequence>].
= Solution
Take $a_n=n$. Every <subsequence> has the form $a_{n_k}=n_k$, with $n_k\ge k$, so it tends to positive infinity and cannot converge to a real number. Thus \b[this <sequence> has no convergent <subsequence>].