document.write( "Question 1184792: Please help me find the limit of 1/(2n+1) + 1/(2n+2) + 1/(2n+3) + ... + 1/(3n) as n goes to +infinity. Thank you! \n" ); document.write( "
Algebra.Com's Answer #815469 by ikleyn(52790)\"\" \"About 
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\n" ); document.write( "Please help me find the limit of 1/(2n+1) + 1/(2n+2) + 1/(2n+3) + ... + 1/(3n) as n goes to +infinity. Thank you!
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document.write( "Consider the sum\r\n" );
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document.write( "    \"S%5Bn%5D\" = \"1%2F%282n%2B1%29\" + \"1%2F%282n%2B2%29\" + \"1%2F%282n%2B3%29\" + ... + \"1%2F%283n%29\".       (1)\r\n" );
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document.write( "You can write it EQUIVALENTLY in the form\r\n" );
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document.write( "    \"S%5Bn%5D\" = \"sum%28%281%2Fn%29%2A%281%2F%282%2Bk%2Fn%29%29%2C+k=1%2C+n%29\".       (2)\r\n" );
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document.write( "This sum is the Riemann sum for the integral of the function  f(x) = \"1%2F%282%2Bx%29\"  over the interval [0,1].\r\n" );
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document.write( "When n tends to infinity (n---> oo), the Riemann sum (2) tends to the integral, which is equal to the difference  F(1) - F(0),\r\n" );
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document.write( "where the primitive (\"antiderivative\")  function  F(x)  is   F(x) = ln(2+x).\r\n" );
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document.write( "This difference  F(1) - F(0)  is  ln(3) - ln(2) = \"ln%283%2F2%29\".\r\n" );
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document.write( "THEREFORE,  lim \"S%5Bn%5D\"  when n tends to infinity  is  \"ln%283%2F2%29\".\r\n" );
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