Prove or disprove: If the sequence $(x_{n})_{n\in\mathbb{N}}\subset \mathbb{R}$ is convergent then $(nx_{n})_{n\in\mathbb{N}}$ is divergent.
The statement is true.
(It would work for some exceptions, like when the limit of the sequence $(x_{n}$) was $0$. Then the sequence would be convergent, too.)
But we don't know what $n$ is, we know it's a natural number. It could be $+\infty$ and this multiplied with a value larger than $0$ equals $\infty $ which makes the second sequences $(nx_{n})$ divergent.
Is everything correct?
This task was taken from an old exam, you get 2 points for solving it correctly. How many points would you give me for this solution?
Edit: The statement is wrong because a counter-example is enough to disprove it (see the counter-example at the beginning in the brackets)!