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3. Prove the statement: If the series 2 an is convergent, then an > 0 as n > 00. Is it also true that if an > 0 as n > oo 71:1 00 then 2 an is convergent? Prove or disprove this direction. n=1 1 4. The series 2 117E?) is convergent. Show that this is so by using the Integral Test and then again by using a Comparison n=1 Test. Hint: In using each test, carefully describe why the test can be used and show all details, including those in the integration. 0" 2n+3n 7r\" I 5. Find the sum of the series: n=1