Math Problem Statement

Graph each quadratic function, find the axis of symmetry, vertex, y-intercept, maximum or minimum point, and then state the domain and range.

Solution

Let's go through each quadratic function, finding the axis of symmetry, vertex, y-intercept, maximum or minimum point, and the domain and range.

Function 1: f(x)=3x26x+1f(x) = 3x^2 - 6x + 1

  1. Axis of Symmetry: The axis of symmetry for a quadratic function ax2+bx+cax^2 + bx + c is given by x=b2ax = -\frac{b}{2a}.

    • Here, a=3a = 3 and b=6b = -6.
    • So, x=623=66=1x = -\frac{-6}{2 \cdot 3} = \frac{6}{6} = 1.
  2. Vertex: Substitute x=1x = 1 into the function to find the y-coordinate of the vertex.

    • f(1)=3(1)26(1)+1=36+1=2f(1) = 3(1)^2 - 6(1) + 1 = 3 - 6 + 1 = -2.
    • Vertex: (1,2)(1, -2).
  3. Y-intercept: The y-intercept is the value of f(x)f(x) when x=0x = 0.

    • f(0)=3(0)26(0)+1=1f(0) = 3(0)^2 - 6(0) + 1 = 1.
    • Y-intercept: (0,1)(0, 1).
  4. Maximum or Minimum: Since a=3>0a = 3 > 0, this parabola opens upwards, so it has a minimum at the vertex.

    • Minimum point: (1,2)(1, -2).
  5. Domain and Range:

    • Domain: All real numbers, (,)(-\infty, \infty).
    • Range: [2,)[-2, \infty), since the minimum value is -2.

Function 2: f(x)=x22x+3f(x) = -x^2 - 2x + 3

  1. Axis of Symmetry:

    • a=1a = -1 and b=2b = -2.
    • x=221=22=1x = -\frac{-2}{2 \cdot -1} = \frac{2}{-2} = -1.
  2. Vertex:

    • Substitute x=1x = -1 into the function.
    • f(1)=(1)22(1)+3=1+2+3=4f(-1) = -(-1)^2 - 2(-1) + 3 = -1 + 2 + 3 = 4.
    • Vertex: (1,4)(-1, 4).
  3. Y-intercept:

    • f(0)=022(0)+3=3f(0) = -0^2 - 2(0) + 3 = 3.
    • Y-intercept: (0,3)(0, 3).
  4. Maximum or Minimum: Since a=1<0a = -1 < 0, this parabola opens downwards, so it has a maximum at the vertex.

    • Maximum point: (1,4)(-1, 4).
  5. Domain and Range:

    • Domain: All real numbers, (,)(-\infty, \infty).
    • Range: (,4](-\infty, 4], since the maximum value is 4.

Function 3: f(x)=x24f(x) = x^2 - 4

  1. Axis of Symmetry:

    • a=1a = 1 and b=0b = 0.
    • x=021=0x = -\frac{0}{2 \cdot 1} = 0.
  2. Vertex:

    • Substitute x=0x = 0 into the function.
    • f(0)=(0)24=4f(0) = (0)^2 - 4 = -4.
    • Vertex: (0,4)(0, -4).
  3. Y-intercept:

    • f(0)=4f(0) = -4.
    • Y-intercept: (0,4)(0, -4).
  4. Maximum or Minimum: Since a=1>0a = 1 > 0, this parabola opens upwards, so it has a minimum at the vertex.

    • Minimum point: (0,4)(0, -4).
  5. Domain and Range:

    • Domain: All real numbers, (,)(-\infty, \infty).
    • Range: [4,)[-4, \infty), since the minimum value is -4.

Would you like more detailed explanations for any of these steps, or do you have further questions?

Additional Related Questions

  1. How do you determine if a quadratic function has a maximum or minimum point?
  2. How can you find the x-intercepts of a quadratic function?
  3. What is the significance of the axis of symmetry in a quadratic function?
  4. How can transformations affect the graph of a quadratic function?
  5. How do the values of aa, bb, and cc in ax2+bx+cax^2 + bx + c affect the shape and position of the graph?

Tip

Remember that the vertex of a quadratic function ax2+bx+cax^2 + bx + c provides the point where the function reaches its maximum or minimum, depending on whether the parabola opens up or down.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Graphing Parabolas

Formulas

Axis of symmetry formula x = -b/(2a)
Vertex calculation
Finding y-intercept by setting x = 0

Theorems

Properties of quadratic functions

Suitable Grade Level

Grades 9-11