# The height of a soccer ball that is kicked from the ground can be approximated by the function y=-16x^2 +32x where y is the height of the soccer ball on feet x seconds after it is kicked. Graph this function. find the soccer balls maximum height, and the time it takes the soccer ball to return to the ground. How would you graph this?

## I will assume you are not taking Calculus, but have studied the quadratic function, and know how to complete the square

y = -16(x^2 - 2x)
= -16(x^2 - 2x + 1 - 1)
= -16( (x-1)^2 - 1)
= -16(x-1)^2 + 16

so the vertex is (1,16)
suggesting that the max height is 16 after 1 second
so it takes 1 second to up and 1 second to come back down, for a total of 2 seconds for the ball to hit the ground again.

graph?
make a table of values of x and y
and plot

http://www.wolframalpha.com/input/?i=plot+y%3D-16x%5E2+%2B32x

## To graph the function y = -16x^2 + 32x, we can start by plotting some points on a coordinate grid and connecting them to form a parabolic shape.

To do this, we can choose different values for x and calculate the corresponding y values using the given equation. Let's choose a few values for x, such as -1, 0, 1, and 2, to find their corresponding y values:

For x = -1:
y = -16(-1)^2 + 32(-1)
= -16 + (-32)
= -48

For x = 0:
y = -16(0)^2 + 32(0)
= 0 + 0
= 0

For x = 1:
y = -16(1)^2 + 32(1)
= -16 + 32
= 16

For x = 2:
y = -16(2)^2 + 32(2)
= -64 + 64
= 0

The points we found are (-1, -48), (0, 0), (1, 16), and (2, 0). Plotting these points on a graph and connecting them will give us a visual representation of the function.

Now, let's calculate the vertex of the parabola to find the maximum height. The vertex of a parabola with the equation y = ax^2 + bx + c can be found using the formula x = -b/(2a).

In this case, a = -16 and b = 32. Plugging these values into the formula, we get:
x = -32 / (2 * -16)
x = -32 / -32
x = 1

To find the maximum height, we substitute x = 1 into the equation y = -16x^2 + 32x:
y = -16(1)^2 + 32(1)
y = -16 + 32
y = 16

So, the soccer ball reaches a maximum height of 16 feet.

To determine the time it takes for the soccer ball to return to the ground, we need to find the x value when y = 0. So, we substitute y = 0 into the equation and solve for x:
0 = -16x^2 + 32x
16x^2 - 32x = 0
x(16x - 32) = 0

This equation has two solutions: x = 0 and 16x - 32 = 0. Solving the second equation:
16x - 32 = 0
16x = 32
x = 2

Therefore, the soccer ball takes 2 seconds to return to the ground.

To summarize:
- The graph of the function is a downward-opening parabola.
- The maximum height of the soccer ball is 16 feet.
- The soccer ball takes 2 seconds to return to the ground.

## To graph the function y = -16x^2 + 32x, you can follow these steps:

1. Determine the domain and range: Since time cannot be negative, the domain of the function is x ≥ 0. The range is y ≥ 0 because height cannot be negative.

2. Calculate key points: To plot the graph, calculate the values of y for various x. You can select some values of x, substitute them into the equation, and find the corresponding y values.

Let's choose x = 0, 1, 2, 3, and 4:
- For x = 0: y = -16(0)^2 + 32(0) = 0.
- For x = 1: y = -16(1)^2 + 32(1) = 16.
- For x = 2: y = -16(2)^2 + 32(2) = 0.
- For x = 3: y = -16(3)^2 + 32(3) = 48.
- For x = 4: y = -16(4)^2 + 32(4) = 64.

Therefore, the key points are (0, 0), (1, 16), (2, 0), (3, 48), and (4, 64).

3. Plot the points: On a graph paper, mark the points you calculated.

4. Draw the graph: Connect the marked points smoothly, forming a parabolic curve. The resulting graph looks like a downward-opening U-shape.

Note: The graph is symmetric with respect to the vertex, which is the maximum point of the function.

To find the maximum height of the soccer ball and the time it takes to return to the ground, we need to analyze the equation y = -16x^2 + 32x.

This equation represents a quadratic function in the form y = ax^2 + bx + c, where:
- a = -16
- b = 32
- c = 0

1. Maximum height: The vertex of a parabolic function in the form y = ax^2 + bx + c is given by the formula x = -b / (2a) and y = f(x).

Plugging in our values:
x = -32 / (2 * -16) = 1
y = -16(1)^2 + 32(1) = 16

Therefore, the maximum height is 16 feet.

2. Time to return to the ground: We need to find the x-intercepts of the function, which represents when y = 0.

Setting y = 0 in our equation:
-16x^2 + 32x = 0

Factoring out an x:
x(-16x + 32) = 0

Setting each factor equal to zero:
x = 0 (This represents the initial time when the ball is kicked from the ground.)
-16x + 32 = 0
-16x = -32
x = 2

Therefore, it takes 2 seconds for the soccer ball to return to the ground.

By following these steps, you should be able to graph the function and find the maximum height and time it takes for the soccer ball to return to the ground.