document.write( "Question 214564: Not sure which topic would fit this best... but if someone could show me how to tackle this question:\r
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document.write( "The sum of two numbers is 30 and their product is a maximum. Find the two numbers. \n" );
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Algebra.Com's Answer #162045 by Alan3354(69443)![]() ![]() You can put this solution on YOUR website! Not sure which topic would fit this best... but if someone could show me how to tackle this question: \n" ); document.write( "The sum of two numbers is 30 and their product is a maximum. Find the two numbers. \n" ); document.write( "------------ \n" ); document.write( "It's always the square, in this case 15 and 15. \n" ); document.write( "15*15 = 225 \n" ); document.write( "14*16 = 224 \n" ); document.write( "13*17 = 221 \n" ); document.write( "See the pattern? \n" ); document.write( "------------ \n" ); document.write( "A rigorous solution: \n" ); document.write( "x*(30-x) = 0 \n" ); document.write( "x^2 - 30x = 0 \n" ); document.write( "The vertex (maximum) is at x = -b/2a \n" ); document.write( "= 30/2 = 15 \n" ); document.write( "---------- \n" ); document.write( "Using calculus: \n" ); document.write( "f(x) = x*(30-x) \n" ); document.write( "f(x) = x^2 - 30x \n" ); document.write( "f'(x) = 2x-30 = 0 \n" ); document.write( "2x-30 = 0 \n" ); document.write( "x = 15 \n" ); document.write( " \n" ); document.write( " |