Math Problem Statement

The diagram shows part of a roller coaster. The graph of the curve H = a(x - h)^2 + k, where H is the height in meters and x is the distance from the starting point for 0 ≤ x ≤ 6. The y-intercept is (0, 19). The vertex is at the point (3, 1), and the point P(5, 9) is on the graph. Solve the following: a) At what height do you begin your roller coaster journey? b) Write down the value of h and k. c) Write down the equation of the curve. d) Using your answer in part c, show that a = 2.

Solution

Let's address each part of the problem step by step.

Given Information:

The equation of the curve is: H=a(xh)2+kH = a(x - h)^2 + k where:

  • HH is the height in meters.
  • xx is the distance from the starting point.
  • The yy-intercept is (0,19)(0, 19).
  • The vertex is at (3,1)(3, 1).
  • Point P(5,9)P(5, 9) is on the graph.

Solution:

a. Starting Height

From the graph, the roller coaster journey begins at the yy-intercept (0,19)(0, 19). Therefore, the starting height is: H=19 metersH = 19 \text{ meters}

b. Values of hh and kk

Since the vertex of the curve is at (3,1)(3, 1), this gives us: h=3andk=1h = 3 \quad \text{and} \quad k = 1

c. Equation of the Curve

Now that we have h=3h = 3 and k=1k = 1, the equation becomes: H=a(x3)2+1H = a(x - 3)^2 + 1 We need to determine the value of aa. We can use the point (0,19)(0, 19), which is on the graph: 19=a(03)2+119 = a(0 - 3)^2 + 1 19=9a+119 = 9a + 1 18=9a18 = 9a a=2a = 2 Thus, the equation of the curve is: H=2(x3)2+1H = 2(x - 3)^2 + 1

d. Verification that a=2a = 2 Using Point P(5,9)P(5, 9)

To verify that a=2a = 2, we substitute the point (5,9)(5, 9) into the equation: 9=2(53)2+19 = 2(5 - 3)^2 + 1 9=2(2)2+19 = 2(2)^2 + 1 9=24+19 = 2 \cdot 4 + 1 9=8+19 = 8 + 1 9=99 = 9 This confirms that our value of a=2a = 2 is correct.

Final Answers:

a. The roller coaster journey starts at a height of 19 meters.

b. The values of hh and kk are 3 and 1, respectively.

c. The equation of the curve is: H=2(x3)2+1H = 2(x - 3)^2 + 1

d. Using the equation, we verified that a=2a = 2.

Would you like more details or have any questions?

Related Questions:

  1. How would the equation change if the vertex was at a different point?
  2. What does the value of aa indicate about the shape of the parabola?
  3. How can you find the vertex form of a parabola if only given three points?
  4. What happens to the graph if the value of kk changes?
  5. Can you find the roots of the equation H=0H = 0?

Tip:

Remember that the vertex form of a quadratic equation, a(xh)2+ka(x - h)^2 + k, makes it easier to determine the maximum or minimum point of the graph directly.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Graphing Parabolas

Formulas

Vertex form of a quadratic equation H = a(x - h)^2 + k
Substitution method for solving quadratic equations

Theorems

Vertex Theorem for Parabolas

Suitable Grade Level

Grades 9-11