The function shown models the height (in feet) of a softball 1 seconds after it
is pitched in an underhand motion. Describe the domain and range. Find the
maximum height of the softball. (Section 8.3)
H(t)= - 16t^2 - 32t- 2

The function shown models the height in feet of a softball 1 seconds after it is pitched in an underhand motion Describe the domain and range Find the maximum h class=

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Answer:

Part 1) The maximum height of the softball is 18 feet

Part 2) The range for H(t) is the interval [0,18]

[tex]0\leq H(t)\leq 18[/tex]

Part 3) The domain is the interval [0,2.06]

[tex]0\leq t\leq 2.06[/tex]

Step-by-step explanation:

step 1

Find the maximum height of the softball

we have

[tex]H(t)=-16t^2+32t+2[/tex]

This is a vertical parabola open downward

The vertex represent a maximum

step 1

Find the maximum height of the ball

we know that

The maximum height of the ball correspond to the y-coordinate of the vertex

Convert the quadratic equation into vertex form

Factor -16

[tex]H(t)=-16(t^2-2t)+2[/tex]

Complete the square

[tex]H(t)=-16(t^2-2t+1)+2+16[/tex]

[tex]H(t)=-16(t^2-2t+1)+18[/tex]

Rewrite as perfect squares

[tex]H(t)=-16(t-1)^2+18[/tex]

The vertex is the point (1,18)

therefore

The maximum height of the softball is 18 feet

step 2

Find the range of the function

The range for H(t) is the interval [0,18]

[tex]0\leq H(t)\leq 18[/tex]

step 3

Find the domain

To find out the domain we need to determine the x-intercepts

For H(t)=0

[tex]0=-16(t-1)^2+18[/tex]

[tex]16(t-1)^2=18[/tex]

[tex](t-1)^2=\frac{18}{16}[/tex]

[tex]t-1=\pm\frac{3\sqrt{2}}{4}[/tex]

[tex]t=\pm\frac{3\sqrt{2}}{4}+1[/tex]

The solutions are

[tex]t=\frac{3\sqrt{2}}{4}+1=2.06\ sec[/tex]

[tex]t=-\frac{3\sqrt{2}}{4}+1=-0.06\ sec[/tex] ---> is not solution because the time cannot be negative

so

The domain is the interval [0,2.06]

[tex]0\leq t\leq 2.06[/tex]