document.write( "Question 1157160: A Norman window is a window with a semi-circle on top of regular rectangular window. (See the picture.) What should be the dimensions of the rectangular part of a Norman window to allow in as much light as possible, if there are only 12 ft of the frame material available? \n" ); document.write( "
Algebra.Com's Answer #779976 by ikleyn(52906)\"\" \"About 
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document.write( "Let x = width and diameter;\r\n" );
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document.write( "    y = height of the rectangle part.\r\n" );
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document.write( "Then the perimeter   \r\n" );
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document.write( "P = \"x+%2B+2y+%2B+%28pi%2Ax%29%2F2%29\"  ====>  \"x+%2B+%28pi%2Ax%29%2F2\" + \"2y\" = 12  ====>  y = \"6+-+x%2F2+-+%28pi%2Ax%29%2F4\".\r\n" );
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document.write( "The area A = \"xy\" + \"%281%2F2%29%2Api%2A%28x%2F2%29%5E2\" = \"x%2A%286-x%2F2+-+%28pi%2Ax%29%2F4%29\" + \"%28pi%2F2%29%2A%28x%2F2%29%5E2\" = \"6x\" - \"x%5E2%2F2\" - \"%28pi%2F4%29%2Ax%5E2\" + \"%28pi%2F8%29%2Ax%5E2\" = \"-x%5E2%2F2\" + \"6x\" - \"%28pi%2F8%29%2Ax%5E2\"\r\n" );
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document.write( "Then  the condition for the maximum area  \"%28dA%29%2F%28dx%29\" = 0  takes the form\r\n" );
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document.write( "\"-x+%2B+6+-+%28pi%2F4%29%2Ax\" = 0,   or   \"x%2A%281%2Bpi%2F4%29\" = 6  ====> x = \"6%2F%281%2Bpi%2F4%29\" = \"6%2F%281+%2B+%283.14%2F4%29%29\" = 3.36 ft.\r\n" );
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document.write( "Answer.  The maximum area is at x = 3.36 ft  (the width), \r\n" );
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document.write( "         y = \"6+-+x%2F2+-+%28pi%2Ax%29%2F4\" = \"6+-+3.36%2F2+-+%283.14%2A3.36%29%2F4\" = 1.68 ft (the height).\r\n" );
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