Math Problem Statement

The function f(t) = 4t2 − 8t + 7 shows the height from the ground f(t), in meters, of a roller coaster car at different times t. Write f(t) in the vertex form a(x − h)2 + k, where a, h, and k are integers, and interpret the vertex of f(t).

f(t) = 4(t − 1)2 + 3; the minimum height of the roller coaster is 1 meter from the ground f(t) = 4(t − 1)2 + 3; the minimum height of the roller coaster is 3 meters from the ground f(t) = 4(t − 1)2 + 2; the minimum height of the roller coaster is 2 meters from the ground f(t) = 4(t − 1)2 + 2; the minimum height of the roller coaster is 1 meter from the ground

Solution

Let's start by rewriting the given quadratic function f(t)=4t28t+7f(t) = 4t^2 - 8t + 7 into the vertex form f(t)=a(th)2+kf(t) = a(t - h)^2 + k.

Step 1: Identify the coefficients

The given function is: f(t)=4t28t+7f(t) = 4t^2 - 8t + 7 Here, a=4a = 4.

Step 2: Complete the square

We need to rewrite the quadratic part 4t28t4t^2 - 8t in a perfect square form.

  1. Factor out the coefficient of t2t^2 from the first two terms: f(t)=4(t22t)+7f(t) = 4(t^2 - 2t) + 7
  2. To complete the square, take half of the coefficient of tt in the parentheses (which is 2-2), square it, and add and subtract this square inside the parentheses. f(t)=4(t22t+11)+7f(t) = 4\left(t^2 - 2t + 1 - 1\right) + 7 f(t)=4((t1)21)+7f(t) = 4\left((t - 1)^2 - 1\right) + 7
  3. Distribute the 4 and simplify: f(t)=4(t1)24+7f(t) = 4(t - 1)^2 - 4 + 7 f(t)=4(t1)2+3f(t) = 4(t - 1)^2 + 3

Step 3: Identify the vertex and interpret it

The function in vertex form is: f(t)=4(t1)2+3f(t) = 4(t - 1)^2 + 3 This tells us that the vertex of the parabola is at (h,k)=(1,3)(h, k) = (1, 3).

Interpretation:

  • The vertex of the function f(t)=4(t1)2+3f(t) = 4(t - 1)^2 + 3 is (1,3)(1, 3).
  • This means that the minimum height of the roller coaster car occurs at t=1t = 1 second, and the minimum height is 33 meters from the ground.

Correct Answer:

The correct interpretation is: \textbf{f(t) = 4(t - 1)^2 + 3; the minimum height of the roller coaster is 3 meters from the ground.}


Would you like more details or have any questions?

Related Questions:

  1. How do you find the vertex of a quadratic function given in standard form?
  2. What is the significance of the coefficient "a" in the vertex form of a quadratic function?
  3. How does the value of "h" in the vertex form relate to the graph of the quadratic function?
  4. Can a quadratic function have a maximum value instead of a minimum? If so, when?
  5. What does the vertex represent in the context of real-world problems, such as projectile motion?
  6. How do you determine the axis of symmetry for a quadratic function?
  7. What happens to the graph of a quadratic function if "a" is negative?
  8. How do you convert a quadratic function from vertex form back to standard form?

Tip:

Completing the square is a powerful method not just for finding the vertex form, but also for solving quadratic equations and integrating certain types of functions.

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Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Vertex Form
Completing the Square

Formulas

Quadratic formula
Vertex form of a quadratic function

Theorems

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Suitable Grade Level

Grades 9-12