A baseball is thrown upwards from a height of 5 feet with an initial speed of 64 feet per second, and its height h (in feet) from the ground is given by h(t) = 5 + 64t – 16t2 as shown in the graph where t is time in seconds. Using a graphing calculator, at what time does the ball reach its maximum height?

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Question

A baseball is thrown upwards from a height of 5 feet with an initial speed of 64 feet per second, and its height h (in feet) from the ground is given by h(t) = 5 + 64t – 16t2 as shown in the graph where t is time in seconds. Using a graphing calculator, at what time does the ball reach its maximum height?

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anonymous · Answer

max is at the vertex

anonymous · Answer

first coordinate of the vertex is $-\frac{b}{2a}$ 
compute that number with $a=-16,b=64$