Math Problem Statement

Use the vertex and intercepts to sketch the graph of the quadratic function. Give the equation for the parabola's axis of symmetry. Use the parabola to identify the function's domain and range.

Solution

Let's break down the given function f(x)=2(x+3)21f(x) = 2(x + 3)^2 - 1 to extract the key information needed for graphing and analyzing it:

1. Vertex of the Parabola

The equation is in vertex form: f(x)=a(xh)2+kf(x) = a(x-h)^2 + k Here, a=2a = 2, h=3h = -3, and k=1k = -1. Thus, the vertex of the parabola is at (3,1)(-3, -1).

2. Axis of Symmetry

The axis of symmetry is the vertical line that passes through the vertex. Hence, the equation of the axis of symmetry is: x=3x = -3

3. Y-Intercept

To find the y-intercept, set x=0x = 0: f(0)=2(0+3)21=2(9)1=181=17f(0) = 2(0 + 3)^2 - 1 = 2(9) - 1 = 18 - 1 = 17 Thus, the y-intercept is (0,17)(0, 17).

4. X-Intercepts

To find the x-intercepts, set f(x)=0f(x) = 0 and solve for xx: 2(x+3)21=02(x + 3)^2 - 1 = 0 2(x+3)2=12(x + 3)^2 = 1 (x+3)2=12(x + 3)^2 = \frac{1}{2} x+3=±12=±22x + 3 = \pm \sqrt{\frac{1}{2}} = \pm \frac{\sqrt{2}}{2} x=3±22x = -3 \pm \frac{\sqrt{2}}{2} The two x-intercepts are approximately: x1=3+222.29andx2=3223.71x_1 = -3 + \frac{\sqrt{2}}{2} \approx -2.29 \quad \text{and} \quad x_2 = -3 - \frac{\sqrt{2}}{2} \approx -3.71

5. Domain and Range

  • Domain: Since this is a parabola, the domain is all real numbers: (,)(-\infty, \infty)
  • Range: The parabola opens upwards (since a=2>0a = 2 > 0), and the minimum value occurs at the vertex (3,1)(-3, -1). Therefore, the range is: [1,)[-1, \infty)

Graphing the Parabola:

  • The vertex is at (3,1)(-3, -1).
  • The y-intercept is at (0,17)(0, 17).
  • The x-intercepts are approximately (2.29,0)(-2.29, 0) and (3.71,0)(-3.71, 0).
  • The axis of symmetry is x=3x = -3.

Would you like further details on any specific part of the solution, or should I help with plotting the graph in more detail?

Here are some additional related questions you can explore:

  1. How does the value of aa affect the width of the parabola?
  2. What would happen if hh or kk were changed in the vertex form equation?
  3. How can you verify the x-intercepts algebraically?
  4. What are other forms of quadratic functions, and how do they differ?
  5. What tools can help you graph this parabola manually or digitally?

Tip: When graphing quadratic functions, always start with the vertex and axis of symmetry, then use additional points like intercepts to get an accurate shape.

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Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Graphing
Vertex Form

Formulas

f(x) = a(x - h)^2 + k
Domain and Range of Functions
Axis of Symmetry

Theorems

Vertex Theorem
Intercept Theorem
Domain and Range

Suitable Grade Level

Grades 9-11