Question 915633
When the equation has the form
{{{ a*x^2 + b*x + c }}}, then the
x-coordinate of the maximum is
at {{{ -b/(2a) }}}
------------------
In this equation:
{{{ h = -16t^2 + 38t }}}
{{{ -b/(2a) = -38/(2*(-16)) }}}
{{{ -b/(2a) = 19/16 }}}
This is the value of {{{ t[max] }}}
in seconds
{{{ t[max] = 1.188 }}} sec
-----------------
{{{ h[max] = -16*(19/16)^2 + 38*(19/16) }}}
{{{ h[max] = -361/16 + 722/16 }}}
{{{ h[max] = 361/16 }}}
{{{ h[max] = 22.563 }}} ft
-----------------
The ball reaches 20 ft, but not 25 ft
Here's the plot:
{{{ graph( 400, 400, -1, 3, -2, 25, -16x^2 + 38x ) }}}