Jada dives off a cliff into the ocean. The vertical path of her dive, in feet, is modeled by the function f(x)=−0.1(x−3)^2

+10, where x is the horizontal distance, and f(x) is the vertical distance.
To capture her experience, Jada asks a friend to record her on a video camera. The camera's view is modeled by the function g(x)=0.67x+3, where x is the horizontal distance, in feet, and g(x) is the vertical distance, in feet, that the camera can capture.
Graph the equations to determine whether the camera will be able to capture Jada's jump before she hits the water. If so, how far above the surface of the water, to the nearest integer, will the camera capture her jump?
A. 7 feet
B. 8 feet
C. 3 feet
D. The camera will not capture her jump.

1 answer

To determine whether the camera will be able to capture Jada's jump before she hits the water, we need to analyze the two functions \( f(x) \) and \( g(x) \) and see if they intersect, which would indicate that the camera captures Jada at that point.

  1. Equations:

    • Jada's dive: \[ f(x) = -0.1(x - 3)^2 + 10 \]
    • Camera's view: \[ g(x) = 0.67x + 3 \]
  2. Intersect the two equations: To find where the camera captures Jada, we set \( f(x) \) equal to \( g(x) \): \[ -0.1(x - 3)^2 + 10 = 0.67x + 3 \] Simplifying this: \[ -0.1(x - 3)^2 + 10 - 3 = 0.67x \] \[ -0.1(x - 3)^2 + 7 = 0.67x \] Rearranging gives: \[ -0.1(x - 3)^2 - 0.67x + 7 = 0 \]

  3. Expand and simplify: Expanding \((x - 3)^2\): \[ (x - 3)^2 = x^2 - 6x + 9 \] Substitute it back: \[ -0.1(x^2 - 6x + 9) - 0.67x + 7 = 0 \] This expands and simplifies to: \[ -0.1x^2 + 0.6x - 0.9 - 0.67x + 7 = 0 \] \[ -0.1x^2 - 0.07x + 6.1 = 0 \] Multiply through by -1 for simplicity: \[ 0.1x^2 + 0.07x - 6.1 = 0 \]

  4. Use the quadratic formula: The quadratic formula is \( x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \) where \( a = 0.1 \), \( b = 0.07 \), and \( c = -6.1 \). \[ b^2 - 4ac = (0.07)^2 - 4(0.1)(-6.1) = 0.0049 + 2.44 = 2.4449 \] \[ x = \frac{-0.07 \pm \sqrt{2.4449}}{0.2} \] \[ x = \frac{-0.07 \pm 1.5655}{0.2} \] Calculating the two potential solutions: \[ x_1 = \frac{1.4955}{0.2} = 7.4775 \] \[ x_2 = \frac{-1.6355}{0.2} = -8.1775 \text{ (not applicable as distance must be positive)} \]

  5. Find the vertical distance when \( x = 7.4775 \): Substitute \( x \) back into either original function. We will use \( g(x) \): \[ g(7.4775) = 0.67(7.4775) + 3 \] \[ g(7.4775) = 5.012525 + 3 = 8.012525 \] Rounding to the nearest integer gives \( 8 \) feet.

  6. Conclusion: The camera will capture Jada's jump at approximately 8 feet above the surface of the water.

Thus, the answer is: B. 8 feet