Discover the best answers at Westonci.ca, where experts share their insights and knowledge with you. Ask your questions and receive detailed answers from professionals with extensive experience in various fields. Get precise and detailed answers to your questions from a knowledgeable community of experts on our Q&A platform.

When a sprinkler is installed in the ground, the spray of water goes up and falls in the pattern of a parabola. The height, in inches, of a spray of water is given by the equation [tex]h(x) = 160x - 16x^2[/tex] where [tex]x[/tex] is the number of feet away from the sprinkler head the spray is.

1. What is the height of the spray 2 feet away from the sprinkler head?
[tex]\[
h(2) = \square
\][/tex]
After 2 feet, the height of the spray is [tex]\square[/tex] inches.

2. How many feet along the ground away from the sprinkler head will the spray reach a maximum height?
[tex]\[
\square \text{ feet}
\][/tex]

3. What is the maximum height of the water spray?
[tex]\[
\square \text{ inches}
\][/tex]

4. How many feet away from the sprinkler head will the water hit the ground again?
[tex]\[
\square \text{ feet}
\][/tex]


Sagot :

Let's break down the solution into several steps:

1. Height of the spray 2 feet away from the sprinkler head:

We use the given formula [tex]\( h(x) = 160x - 16x^2 \)[/tex] to find the height when [tex]\( x = 2 \)[/tex].
[tex]\[ h(2) = 160 \times 2 - 16 \times 2^2 \][/tex]
Simplifying inside the equation:
[tex]\[ h(2) = 320 - 16 \times 4 \][/tex]
[tex]\[ h(2) = 320 - 64 \][/tex]
[tex]\[ h(2) = 256 \][/tex]
Therefore, after 2 feet, the height of the spray is [tex]\( \boxed{256} \)[/tex] inches.

2. Distance along the ground where the spray reaches maximum height:

The height function [tex]\( h(x) = 160x - 16x^2 \)[/tex] represents a parabola that opens downwards (since the coefficient of [tex]\( x^2 \)[/tex] is negative). The maximum height occurs at the vertex of the parabola.

For a quadratic equation in the form [tex]\( ax^2 + bx + c \)[/tex], the x-coordinate of the vertex is given by:
[tex]\[ x = -\frac{b}{2a} \][/tex]
Here, [tex]\( a = -16 \)[/tex] and [tex]\( b = 160 \)[/tex]. Substituting these values in:
[tex]\[ x = -\frac{160}{2 \times -16} \][/tex]
[tex]\[ x = -\frac{160}{-32} \][/tex]
[tex]\[ x = 5 \][/tex]

So, the spray reaches its maximum height at [tex]\( \boxed{5} \)[/tex] feet away from the sprinkler head.

3. Maximum height of the water spray:

We already found the x-coordinate where the maximum height occurs (5 feet away). To find the maximum height:
[tex]\[ h(5) = 160 \times 5 - 16 \times 5^2 \][/tex]
Simplifying inside the equation:
[tex]\[ h(5) = 800 - 16 \times 25 \][/tex]
[tex]\[ h(5) = 800 - 400 \][/tex]
[tex]\[ h(5) = 400 \][/tex]

Therefore, the maximum height of the water spray is [tex]\( \boxed{400} \)[/tex] inches.

4. Distance away from the sprinkler head where the water hits the ground again:

The water hits the ground whenever the height [tex]\( h(x) \)[/tex] is zero. Therefore, we solve the equation:
[tex]\[ 0 = 160x - 16x^2 \][/tex]
Factoring out the common terms:
[tex]\[ 0 = x (160 - 16x) \][/tex]
This gives us two solutions:
[tex]\[ x = 0 \quad \text{or} \quad 160 - 16x = 0 \][/tex]
Solving [tex]\( 160 - 16x = 0 \)[/tex]:
[tex]\[ 160 = 16x \][/tex]
[tex]\[ x = 10 \][/tex]

Therefore, the water hits the ground again at [tex]\( \boxed{10} \)[/tex] feet away from the sprinkler head.