document.write( "Question 988965: please help me on this one....A farmer has 60m of fencing to make a rectangular pen for his goat, find the maximum possible area of the pen.... i tried to derive the expression : l=30-w. And the expression for the area in terms of the width : A=-w^2 +30w \n" ); document.write( "
Algebra.Com's Answer #609433 by josgarithmetic(39618)\"\" \"About 
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length L
\n" ); document.write( "width w
\n" ); document.write( "A for AREA\r
\n" ); document.write( "\n" ); document.write( "perimeter is 60 feet, equal to the amount of fencing.
\n" ); document.write( "\"2w%2B2L=60\"
\n" ); document.write( "\"w%2BL=30\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"A=wL\"
\n" ); document.write( "\"A=w%2830-w%29\"
\n" ); document.write( "\"A=30w-w%5E2\"
\n" ); document.write( "\"A=-w%5E2%2B30w\"------Just as you have.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Your question is, what is w and L for maximum area A ?\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "w and L must be each greater than 0.
\n" ); document.write( "A is a parabola function and \"A=-w%5E2%2B30w\" has a maximum point for its vertex; and A has two x-axis intercepts. The maximum value for A occurs in the exact middle of the roots. w is really the HORIZONTAL number line and A is for the vertical number line. \r
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\n" ); document.write( "\n" ); document.write( "Roots for A?
\n" ); document.write( "\"-w%5E2%2B30w=0\"
\n" ); document.write( "Solve for w, and find what is the value in the middle?
\n" ); document.write( "Now, what is A at that middle value of w?
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