Math Problem Statement

Solve the inequality f(x) > 0, where f(x) = x^2(x + 2), by using the graph of the function.

Solution

To solve the inequality f(x)>0f(x) > 0 for the function f(x)=x2(x+2)f(x) = x^2(x + 2) using the graph, we need to identify the intervals where the function's values are positive.

  1. Identify the roots:

    • From the graph, it looks like f(x)=0f(x) = 0 at x=2x = -2 and x=0x = 0 (the points where the curve crosses the x-axis).
  2. Analyze the sign of f(x)f(x) in intervals:

    • For x<2x < -2, the graph is below the x-axis, so f(x)<0f(x) < 0.
    • Between x=2x = -2 and x=0x = 0, the graph is above the x-axis, meaning f(x)>0f(x) > 0.
    • For x>0x > 0, the graph is also above the x-axis, so f(x)>0f(x) > 0.
  3. Solution in interval notation:

    • The function is positive for x(2,0)(0,)x \in (-2, 0) \cup (0, \infty).

So, the solution set for f(x)>0f(x) > 0 is: (2,0)(0,)(-2, 0) \cup (0, \infty)

Would you like more details on how the function behaves in each interval or have any other questions?


Here are some related questions to deepen understanding:

  1. How would the solution change if the inequality was f(x)0f(x) \geq 0?
  2. What is the effect of changing f(x)f(x) to f(x)=x2(x+2)2f(x) = x^2(x + 2)^2?
  3. How do we interpret the multiplicity of roots when analyzing the graph of a polynomial?
  4. Can you identify intervals where f(x)<0f(x) < 0 based on this graph?
  5. How would the graph change if we added a constant term to f(x)f(x), like f(x)=x2(x+2)+1f(x) = x^2(x + 2) + 1?

Tip: When finding intervals for polynomial inequalities, check the roots and analyze the sign of the function in each interval between the roots.

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Math Problem Analysis

Mathematical Concepts

Polynomial Inequalities
Roots of Polynomials
Graph Analysis

Formulas

Polynomial function: f(x) = x^2(x + 2)

Theorems

Intermediate Value Theorem
Sign analysis of polynomial intervals

Suitable Grade Level

Grades 10-12