anonymous one year ago A toy rocket was launched from the ground. The function f(x) = -16x2 + 160x shows the height of the rocket f(x), in feet, from the ground at time x seconds. What is the axis of symmetry of the graph of f(x), and what does it represent?

1. anonymous

x = 10; it takes 10 seconds to reach the maximum height and 10 seconds to fall back to the ground x = 10; it takes 10 seconds to reach the maximum height and 20 seconds to fall back to the ground x = 5; it takes 5 seconds to reach the maximum height and 10 seconds to fall back to the ground x = 5; it takes 5 seconds to reach the maximum height and 5 seconds to fall back to the ground

2. campbell_st

the axis of symmetry is used in the general quadratic formula and is $t = \frac{-b}{2 \times a}$ in your question a = -16 and b = 160 just substitute the values to axis of symmetry

3. campbell_st

the axis is symmetry is where the rocket reaches it's maximum height.

4. anonymous

okay so then you would want to put in either 5 or 10 into the equation?

5. campbell_st

|dw:1439929604987:dw| the vertex is where the rocket reaches its maximum height... so substitute the value from the axis of symmetry to get the max height

6. anonymous

Ohhh okay so it would be the last one because the line of symmetry is 5 and it takes 5 seconds to get there and 5 more to go back down which is where they are getting the 10 ok

7. anonymous

Thanks