Let $\sum y_n$ diverge. Then there exists a sequence $x_n$ such that $\lim_{n\rightarrow\infty}x_n=0$ and $\sum x_ny_n$ diverges.
Is this true? How should I prove this?
Let $\sum y_n$ diverge. Then there exists a sequence $x_n$ such that $\lim_{n\rightarrow\infty}x_n=0$ and $\sum x_ny_n$ diverges.
Is this true? How should I prove this?