Questions
Question 1
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State the \(p\)-series convergence rule for \(\sum_{n=1}^{\infty}1/n^q\).
Question 2
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What does \(\rho=1\) mean in the ratio test?
Question 3
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Use the \(p\)-series rule to classify \(\sum_{n=1}^{\infty}1/n^3\).
Question 4
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Use the term test on \(\sum_{n=1}^{\infty}\frac{2n+1}{n}\).
Question 5
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Apply the ratio test to \(\sum_{n=1}^{\infty}1/n!\).
Question 6
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Apply the root test to \(\sum_{n=1}^{\infty}(1/5)^n\).
Question 7
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Use comparison to show \(\sum_{n=1}^{\infty}1/(n^2+4)\) converges.
Question 8
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Use comparison to show \(\sum_{n=1}^{\infty}\frac{n+1}{n}\) diverges.
Question 9
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Apply the ratio test to \(\sum_{n=1}^{\infty} n^2/2^n\).
Question 10
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Use limit comparison with \(1/n^2\) for \(\sum_{n=1}^{\infty}\frac{3n+1}{n^3+2}\).
Question 11
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Explain why the integral test requires positivity and decreasing behavior on the tail.
Question 12
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A ratio test gives \(\rho=3/2\). What conclusion follows, and why?
Question 13
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Use the root test on \(\sum_{n=1}^{\infty}\left(\frac{n}{2n+1}\right)^n\).
Question 14
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Use the integral test to classify \(\sum_{n=2}^{\infty}1/(n\ln n)\).
Question 15
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For which real \(p\) does \(\sum_{n=1}^{\infty}1/n^{2p}\) converge?
Question 16
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Classify \(\sum_{n=1}^{\infty}\frac{5^n}{n!}\) using the ratio test.
Question 17
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Classify \(\sum_{n=1}^{\infty}\frac{n!}{3^n}\) using the ratio test.
Question 18
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Diagnose the error: the ratio test gives \(\rho=1\), so the series converges.
Question 19
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Choose and justify a test for \(\sum_{n=1}^{\infty}\frac{2n^2+1}{n^4+n}\).
Question 20
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A learner tries the ratio test on \(\sum1/n^2\) and gets \(\rho=1\). Give a better conclusion and method.