document.write( "Question 1151022: . In the United Parcel Services example at the beginning , the length plus girth of a package was restricted to 108 inches. Suppose a shipper uses rectangular boxes with square ends made of a perforated material to provide ventilation, the shipper wants the total surface area to be as large as possible. Use x as the side of the square base and L as the length.
\n" ); document.write( "a) Write the expression for the area, A, in terms of L and x.
\n" ); document.write( "b) Express A(x) as a function of x alone.
\n" ); document.write( "c) What value of x maximizes A(x)? Prove this is a maximum.
\n" ); document.write( "d) What are the dimensions of the maximum-area box?
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Algebra.Com's Answer #772613 by josgarithmetic(39617)\"\" \"About 
You can put this solution on YOUR website!
If \"restricted to\" means equal to then the system of equations \"system%28L%2B4x=108%2CA=2x%5E2%2B4Lx%29\" fits the description.\r
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\n" ); document.write( "\n" ); document.write( "Substituting and simplifying gives \"A=432x-14x%5E2\".\r
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\n" ); document.write( "\n" ); document.write( "\"dA%2Fdx=432-28x=0\"\r
\n" ); document.write( "\n" ); document.write( "\"108-7x=0\"\r
\n" ); document.write( "\n" ); document.write( "\"108=7x\"\r
\n" ); document.write( "\n" ); document.write( "\"highlight%28x=15.43%29\"\"inches\"\r
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\n" ); document.write( "\n" ); document.write( "\"L=108-4x\"
\n" ); document.write( "\"L=108-4%2A15.43\"
\n" ); document.write( "\"highlight%28L=46.29%29\"\"inches\"
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