Let's solve each question step by step.
Question 1 A)
The height of the football is given by the equation: \[ h = -16t^2 + 60t + 0 \]
To find the maximum height, we can calculate the vertex (maximum point) of the parabola represented by the quadratic equation, since it opens downward (the coefficient of \( t^2 \) is negative).
The formula for the time \( t \) at which the maximum height occurs in a quadratic equation of the form \( ax^2 + bx + c \) is: \[ t = -\frac{b}{2a} \]
Here, \( a = -16 \) and \( b = 60 \): \[ t = -\frac{60}{2 \times -16} = \frac{60}{32} = 1.875 \text{ seconds} \]
Now, substituting \( t = 1.875 \) back into the height equation to find the maximum height \( h \): \[ h = -16(1.875)^2 + 60(1.875) \] \[ h = -16(3.515625) + 112.5 \] \[ h \approx -56.25 + 112.5 \] \[ h \approx 56.25 \]
So, the maximum height is approximately: 56.25 feet.
Question 2 A)
The area \( A \) is modeled by: \[ A = -w^2 + 60w \]
It's a downward-opening parabola, and its maximum area can be found by locating the vertex.
Using the same vertex formula: \[ w = -\frac{b}{2a} \] Here, \( a = -1 \) and \( b = 60 \): \[ w = -\frac{60}{2 \times -1} = \frac{60}{2} = 30 \]
Now substituting \( w = 30 \) back into the area equation: \[ A = -(30)^2 + 60(30) \] \[ A = -900 + 1800 \] \[ A = 900 \]
Thus, the maximum area the fence can have is: 900 square feet.
Question 3 A)
To find the y-value that corresponds to \( x = -1 \) for the function: \[ f(x) = 2x^2 - 2x \] Substituting \( x = -1 \): \[ f(-1) = 2(-1)^2 - 2(-1) \] \[ f(-1) = 2(1) + 2 \] \[ f(-1) = 2 + 2 \] \[ f(-1) = 4 \]
The y-value at \( x = -1 \) is: 4.
Question 4 A)
To find the x-intercepts of the function: \[ f(x) = 2x^2 - 2x \] Setting \( f(x) = 0 \): \[ 2x(x - 1) = 0 \]
This gives us \( x = 0 \) and \( x = 1 \). Therefore, the x-intercepts are indeed \( (0, 0) \) and \( (1, 0) \).
Thus, the statement is: 1 (true).
Question 5 A)
To find the spending that achieves maximum profit in: \[ P = -5x^2 + 1000x + 5000 \] Using the vertex formula: \[ x = -\frac{b}{2a} \] Where \( a = -5 \) and \( b = 1000 \): \[ x = -\frac{1000}{2 \times -5} = \frac{1000}{10} = 100 \]
The maximum profit occurs when: 100 thousands of dollars (or $100,000) are spent on marketing.
Summary of Answers:
- 56.25 feet
- 900 square feet
- 4
- 1
- 100,000 dollars