document.write( "Question 1088456: The sum of the radius and height of a cylinder is 20 cm. The dimensions are whole numbers.
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document.write( "What is the largest possible volume of this cylinder?
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document.write( "Answer in terms of π. \n" );
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Algebra.Com's Answer #702748 by Boreal(15235) You can put this solution on YOUR website! radius is x \n" ); document.write( "height is 20-x \n" ); document.write( "volume is pi*r^2*h=pi*x^2(20-x)=pi(20x^2-x^3) \n" ); document.write( "maximize this \n" ); document.write( "take the derivative and get -3x^2+40x, and set it equal to 0 \n" ); document.write( "3x^2-40x=0 \n" ); document.write( "factor out an x and divide by 3, moving the constant, x=40/3 \n" ); document.write( "whole number dimension for radius is 13 largest whole number. \n" ); document.write( "height is 7 cm \n" ); document.write( "volume is pi (169)*7=1183 pi ANSWER \n" ); document.write( "check with height of 8 and volume of 12=1152 pi \n" ); document.write( "check with height of 6 and volume of 14=1176 pi \n" ); document.write( " \n" ); document.write( " |