Answer: The maximum height of the arrow is the vertex of the parabola. To find this, we can set the derivative of the function equal to zero and solve for x.
y' = -32x + 100
Setting y' = 0 and solving for x:
0 = -32x + 100
32x = 100
x = 100/32
So the arrow reaches its maximum height of y = -16(100/32)² + 100(100/32) + 4 = 100 feet at x = 100/32 seconds after it is shot into the air.
Explanation: