Serie convergenta oare?

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Cezar Lupu
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Serie convergenta oare?

Post by Cezar Lupu »

Hmmm gandindu-ma asa la diverse serii si fiind inspirat de acest topic, ma intreb oare daca seria \( \sum_{n \ge 1}\frac{\sqrt{p_{n+1}}-\sqrt{p_{n}}}{n^{2}} \) este convergenta?

Remarca

Daca luam in seama valabilitatea conjecturii lui Andrica, i.e. \( \sqrt{p_{n+1}}-\sqrt{p_{n}}<1 \), atunci seria noastra ar fi majorata de seria \( \zeta(2)=\sum_{n\ge 1}\frac{1}{n^{2}}=\frac{\pi^{2}}{6} \), deci ar fi convergenta. :)
Last edited by Cezar Lupu on Fri Apr 04, 2008 8:55 pm, edited 2 times in total.
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Dragos Fratila
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Post by Dragos Fratila »

Pai sigur ca e convergenta ca doar ai pus problema domnului Panaitopol mai inainte care e mai tare decat asta (problema e la fel dar fara radicali).
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Beniamin Bogosel
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Post by Beniamin Bogosel »

Pai chiar in topicul tau de acolo, seria nu e la numitor cu \( n \), iar aici mai mult, cu \( n^2 \), deci evident e convergenta.... :)
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