Math Problem Statement

Given the quadratic function f(x) = 2(x - 1)^2 + 5: (a) Sketch the graph of f(x) and show your work by writing all the steps. (b) Write the equation for the function's axis of symmetry. (c) Identify the domain and range of the function.

Solution

The given problem involves a quadratic function f(x)=2(x1)2+5f(x) = 2(x - 1)^2 + 5. It asks for the following:

Part (a)

Sketch the graph of f(x)f(x) with all steps:

To sketch the graph, let's break it down:

  1. Standard form of the function:
    The given function f(x)=2(x1)2+5f(x) = 2(x - 1)^2 + 5 is in vertex form: f(x)=a(xh)2+k,f(x) = a(x - h)^2 + k, where (h,k)(h, k) is the vertex, and a=2a = 2 determines the direction and steepness of the parabola. Here:

    • Vertex: (h,k)=(1,5)(h, k) = (1, 5),
    • a=2a = 2: The parabola opens upward and is vertically stretched.
  2. Axis of symmetry: The axis of symmetry is the vertical line passing through the vertex, i.e., x=1x = 1.

  3. Key points: Substitute values of xx around the vertex to determine key points for the parabola:

    • For x=0x = 0: f(0)=2(01)2+5=2(1)+5=7Point: (0,7).f(0) = 2(0 - 1)^2 + 5 = 2(1) + 5 = 7 \quad \text{Point: } (0, 7).
    • For x=2x = 2 (symmetric to x=0x = 0): f(2)=2(21)2+5=2(1)+5=7Point: (2,7).f(2) = 2(2 - 1)^2 + 5 = 2(1) + 5 = 7 \quad \text{Point: } (2, 7).
    • For x=1x = -1: f(1)=2((1)1)2+5=2(4)+5=13Point: (1,13).f(-1) = 2((-1) - 1)^2 + 5 = 2(4) + 5 = 13 \quad \text{Point: } (-1, 13).
    • For x=3x = 3 (symmetric to x=1x = -1): f(3)=2(31)2+5=2(4)+5=13Point: (3,13).f(3) = 2(3 - 1)^2 + 5 = 2(4) + 5 = 13 \quad \text{Point: } (3, 13).
  4. Graph the points: Plot the vertex (1,5)(1, 5), points (0,7)(0, 7), (2,7)(2, 7), (1,13)(-1, 13), and (3,13)(3, 13). Then draw a smooth upward parabola.


Part (b)

Equation of the axis of symmetry: x=1x = 1


Part (c)

Domain and range of the function:

  1. Domain: Since f(x)f(x) is a quadratic function, it is defined for all real values of xx. Thus: Domain: (,).\text{Domain: } (-\infty, \infty).

  2. Range: The vertex (1,5)(1, 5) gives the minimum value of f(x)f(x), and the parabola opens upwards. Hence: Range: [5,).\text{Range: } [5, \infty).


Would you like a plotted graph or further clarification?

Here are 5 relative questions for deeper understanding:

  1. How does the value of aa affect the steepness and direction of the parabola?
  2. What would change in the graph if the vertex were shifted to (2,3)(-2, 3)?
  3. How can you determine the axis of symmetry directly from the vertex form?
  4. What are the key differences between standard form and vertex form of a quadratic function?
  5. How would the graph change if a=2a = -2 instead of 22?

Tip: Use symmetry when graphing quadratic functions—it simplifies calculations and ensures accuracy.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Graphing Parabolas

Formulas

Vertex form of a quadratic function: f(x) = a(x - h)^2 + k
Axis of symmetry: x = h

Theorems

Properties of quadratic functions
Symmetry of parabolas

Suitable Grade Level

Grades 8-10