A toy rocket was launched from the ground. The function f(x) = -16x2 + 192x shows the height of the rocket f(x), in feet, from the ground at time x seconds.

Question

anonymous · Answer

What is the axis of symmetry of the graph of f(x) and what does it represent?

x = 12; it takes 12 seconds to reach the maximum height and 12 seconds to fall back to the ground

x = 12; it takes 12 seconds to reach the maximum height and 24 seconds to fall back to the ground

x = 6; it takes 6 seconds to reach the maximum height and 6 seconds to fall back to the ground

x = 6; it takes 6 seconds to reach the maximum height and 3 seconds to fall back to the ground

reemii · Answer

do you think you must locate the axis of symmetry using derivatives or the zeros of the function?

anonymous · Answer

I'm unsure of the entire thing

reemii · Answer

|dw:1400386052415:dw|
the graph of the function is a parabola. it must look like this ("$-$" sign in front of the $x^2$ term). agree ?

reemii · Answer

a parabola always has an axis of symmetry.

It is turned upside down because of the negative coefficient in front of the $x^2$ term.

|dw:1400386470983:dw|
where does the dashed line cut the axis ? (describe it at least using other points of the graph)