Question 1023080
{{{ y = x*( 60 - x ) }}}
{{{ y = -x^2 + 60x }}}
This is a parabola with a maximum because
of the minus sign in front of the {{{ x^2 }}} term
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The formula for x-coordinate of maximum is:
{{{ x[max] = -b/(2a) }}}
{{{ a = -1 }}}
{{{ b = 60 }}}
{{{ x[max] = -60/(2*(-1)) }}}
{{{ x[max] = 30 }}}
The width is 30 yds
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check:
{{{ y = x*( 60 - x ) }}}
{{{ y = 30*( 60 - 30 ) }}}
{{{ y = 900 }}} yds2
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Try {{{ x = 29 }}} and {{{ x = 31 }}}
You should get less than {{{ 900 }}} yds2
also:
Let {{{ P }}} = perimeter
{{{ P = 2x + 2*( 60 - x ) }}}
{{{ P = 2*30 + 2*( 60 - 30 ) }}}
{{{ P = 60 + 60 }}}
{{{ P = 120 }}}
OK