document.write( "Question 292749: Hi\r
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document.write( "How exactly do I do b + c of this question?\r
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document.write( "a) Using a large scale, sketch the curve y =1/x between the values of x = 1 and x=2. \r
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document.write( "b) Divide the interval into n equal parts and by comparing the area under the curve, with the areas of suitable rectangles, show that 1/n * (n/(n+1) + n/(n+2) + ... + n/2n)< log2 < 1/n * (1 + n/(n+1) + n/(n+2) + ... + n/(2n-1)\r
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document.write( "c) lim (n -> infinity) [n/(n+1)+ n/(n+2)+ ... + n/2n] = log2 \n" );
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Algebra.Com's Answer #211403 by stanbon(75887)![]() ![]() ![]() You can put this solution on YOUR website! a) Using a large scale, sketch the curve y =1/x between the values of x = 1 and x=2. \n" ); document.write( "--- \n" ); document.write( "Do as directed. Draw the curve over that interval. Make it large enough \n" ); document.write( "so you can see what you are doing. \n" ); document.write( "---------------------------------- \n" ); document.write( "Comment: Note that the width of each base interval is 1/n. \n" ); document.write( "---------------------------------- \n" ); document.write( "b) Divide the interval into n equal parts and by comparing the area under the curve, with the areas of suitable rectangles, show that 1/n * [n/(n+1) + n/(n+2) + ... + n/2n])< log2 < 1/n * [1 + n/(n+1) + n/(n+2) + ... + n/(2n-1)] \n" ); document.write( "Note: The 1st base interval goes from 1 to 1+1/n = (n+1)/n \n" ); document.write( "The height of the curve at x = 1 is 1 \n" ); document.write( "The height of the curve at x = 1 + 1/n is n/(n+1) \n" ); document.write( "The height of the curve at x = 1 + 2/n is n/(n+2) etc \n" ); document.write( "-- \n" ); document.write( "Draw a few rectangles UNDER the curve, with 1/n as base and height equal \n" ); document.write( "to the height of the curve at x = 1 then 1+1/n then 1+2/n etc. \n" ); document.write( "-------------------------------------------------------------------- \n" ); document.write( "The sum of those areas is less than the area under the curve from [1,2].\ \n" ); document.write( "--------------------- \n" ); document.write( "Now draw a few rectangles that extend ABOVE the curve with 1/n as base \n" ); document.write( "and height equal to 1+1/n then 1+2/n then 1+3/n etc \n" ); document.write( "----------------------- \n" ); document.write( "The sum of those areas is greater than the area under the curve from [1,2] \n" ); document.write( "==================================================\r \n" ); document.write( "\n" ); document.write( "c) lim (n -> infinity) [n/(n+1)+ n/(n+2)+ ... + n/2n] = log2 \n" ); document.write( "If you go thru the process with a few values of \"n\" you will see \n" ); document.write( "that, as n gets larger, the sums get closer to log(2) \n" ); document.write( "---------------------------- \n" ); document.write( "As you increase the number of rectangles by increasing \"n\" the area \n" ); document.write( "sum of the areas under the curve and sum of the areas over the curve \n" ); document.write( "get closer to the true area under the curve, which is log(2) \n" ); document.write( "====================================================================== \n" ); document.write( "Cheers, \n" ); document.write( "Stan H. \n" ); document.write( "==================== \n" ); document.write( " |