Recent content by kris11

Ohh thank you! So for the first part you used Cauchy-Schwarz inequality, right? And can I prove it by using real numbers, eg for $$a_{n}$$=2, and n=8 ?

Yeah, I think I can prove it, however I cannot use this method as I never learn it before. So far for this kind of questions I learned tests for convergence, eg ratio test, root test, integral test... etc :) So I think my teacher wants me to solve this question using these methods. But thank you...

Hi Everyone :) Thank you for all your replies :) I still haven't done this question :( I don't know what Cauchy–Schwarz inequality is, but I looked for this inequality on the internet and tried to apply it to my question but it didn't work. I also tried convergence tests but I gave up. I can do...

Assume that $$\sum_{n=1}^{\infty} a^2_{n}$$ converge, and assume that $$a_{n}$$ is non-negative for all $$\textit{n} \in N.$$ Determine whether the following statement is true (and prove it) or false (and give counterexample). $$\sum_{n=2}^{\infty} \frac{a_{n}}{n^{2/3}}<\infty$$ Does anyone...