Problem 190 (difficulty: 2/10)
Is it true that if \(\displaystyle x_n\) is convergent, \(\displaystyle y_n\) is divergent then \(\displaystyle x_ny_n\) is divergent?
Solution:
No, for example \(\displaystyle x_n=\frac1{n^2}\) and \(\displaystyle y_n=n\).