math
posted by Anonymous on .
A baseball player swings and hits a pop fly straight up in the air to the catcher. The height of the baseball in meters t seconds after it is hit is given by a quadratic function h(t) = −4.9t^2 + 9.8t + 1. What is the maximum height of the baseball?

If you know Calculus,
h ' (t) = 9.8t + 9.8 = 0 for a max of h
9.8t = 9.8
t = 1
h(1) = 4/9(1) + 9.8 + 1 = 5.9 m
If you don't know Calculus, complete the square
h(t) = 4.9 [t^2  2t +1  1 ] +1
= 4.9 [ (t1)^2  1 ] + 1
= 4.9(t1)^2 + 4.9 + 1
= 4.9(t1)^2 + 5.9
so the vertex is (1,5.9) and the parabola opens downwards
So we have a maximum of 5.9 m when t = 1 sec 
Bleh