Math Problem Statement

Use the function f(x) = x^4 - x^2 to analyze the graph's behavior, find x-intercepts, and determine where the graph crosses or touches the x-axis.

Solution

The problem asks to analyze the function f(x)=x4x2f(x) = x^4 - x^2 and complete several parts. Here's a breakdown of the answers from the image:

  1. Part (a) - Leading Coefficient Test:

    • The function f(x)=x4x2f(x) = x^4 - x^2 is a quartic function (degree 4), and its leading term is x4x^4, which is positive.
    • According to the Leading Coefficient Test:
      • For even-degree functions with a positive leading coefficient, the graph rises to the left and rises to the right.
    • Correct answer: C (The graph of f(x)f(x) rises left and rises right).
  2. Part (b) - Finding x-intercepts:

    • To find the x-intercepts, set f(x)=0f(x) = 0: x4x2=0x^4 - x^2 = 0 Factor the expression: x2(x21)=0x^2(x^2 - 1) = 0 This gives two factors: x2=0orx21=0x^2 = 0 \quad \text{or} \quad x^2 - 1 = 0 Solving: x=0orx=±1x = 0 \quad \text{or} \quad x = \pm 1 Thus, the x-intercepts are x=0,1,1x = 0, 1, -1.
    • Correct answer: x = 0, 1, -1.
  3. Part (c) - At which zeros does the graph cross the x-axis:

    • The graph crosses the x-axis at points where the multiplicity of the root is odd. In this case:
      • For x=0x = 0, the root comes from x2=0x^2 = 0, which has even multiplicity, so it doesn't cross here (the graph touches the x-axis but doesn't cross).
      • For x=±1x = \pm 1, these come from linear factors, so the multiplicity is odd, and the graph crosses the x-axis at these points.
    • Correct answer: A (x = 1, -1).
  4. Part (d) - At which zeros does the graph touch the x-axis and turn around:

    • The graph touches the x-axis and turns around at points where the multiplicity of the root is even.
    • For x=0x = 0, the root x2=0x^2 = 0 has even multiplicity.
    • Correct answer: A (x = 0).

Let me know if you'd like further clarification or details on any of these points!

Related Questions:

  1. What is the significance of the leading coefficient in determining end behavior?
  2. How does the multiplicity of roots affect whether the graph crosses or touches the x-axis?
  3. Why does a degree-4 polynomial have certain types of end behaviors?
  4. Can a graph both touch and cross the x-axis at the same root?
  5. How can factoring help in finding the x-intercepts of higher-degree polynomials?

Tip:

When solving polynomials, always check the multiplicity of roots to determine whether the graph crosses or merely touches the x-axis.

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Math Problem Analysis

Mathematical Concepts

Polynomial Functions
Factoring
Leading Coefficient Test
Multiplicity of Roots

Formulas

f(x) = x^4 - x^2
Factoring: f(x) = x^2(x^2 - 1) = x^2(x - 1)(x + 1)

Theorems

Leading Coefficient Test
Multiplicity of Roots

Suitable Grade Level

Grades 10-12