<PRE><B>Question 861543</B>
S=7t-4.9t^2
The precalculus solution is to graph the equation
{{{ graph( 300, 200, -4, 4, -3, 3, -4.9x^2 +7x) }}}
from the graph we see t = 0.7 seconds and the max height is 2.5 meters
the calculus solution is to take the first derivative and set it = 0
S&#39; = 7 - 9.8t
7 - 9.8t = 0
9.8t = 7
t = 7/9.8 = 0.71
then substitute for t in orignal equation
S = 7*(0.71) - 4.9*(0.71)^2
S = 2.5
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