Math Problem Statement

What is missing in this or what is incorrect in the answer

Find a possible equation for the polynomial function, y = P(x), whose graph is given in the image.

Solution

In the answer written on the paper, there are several points to examine:

  1. Roots of the Polynomial: The graph shows the polynomial passing through several x-intercepts: x=3x = -3, x=0x = 0, and x=2.5x = 2.5. These indicate that factors of the polynomial should include (x+3)(x + 3), xx, and (x2.5)(x - 2.5).

  2. Multiplicity of Roots:

    • At x=3x = -3, the curve touches the x-axis and turns around, indicating that (x+3)(x + 3) has a multiplicity of 2 (a repeated root).
    • At x=0x = 0, the curve also behaves similarly, touching the x-axis and turning back, which suggests xx also has a multiplicity of 2.
    • At x=2.5x = 2.5, the curve crosses the x-axis, indicating a single root.
  3. General Form of the Polynomial: Given these observations, the polynomial should look something like: P(x)=a(x+3)2x2(x2.5)P(x) = a \cdot (x + 3)^2 \cdot x^2 \cdot (x - 2.5) where aa is a constant that could be determined if we had a specific point on the graph (other than the roots) to substitute and solve for aa.

  4. Checking the Answer on Paper: The answer provided on the paper reads: P(x)=(x2.5)(x+3)2P(x) = (x - 2.5)(x + 3)^2 This answer misses the x2x^2 factor, which represents the root at x=0x = 0 with a multiplicity of 2. The correct answer should therefore include x2x^2 to accurately match the given graph's behavior at the origin.

In summary, the correct form should be: P(x)=a(x+3)2x2(x2.5)P(x) = a \cdot (x + 3)^2 \cdot x^2 \cdot (x - 2.5) where aa is a scaling factor, often assumed to be 1 unless specified otherwise.

Would you like further clarification on how to determine the constant aa or on any other aspect?


Here are five questions that build on this explanation:

  1. Why does the behavior of the graph at each root affect the multiplicity in the polynomial?
  2. How would you find the value of aa if another point on the graph was given?
  3. What would happen if the polynomial lacked the x2x^2 factor entirely?
  4. How does the multiplicity of a root influence the shape of the graph at that root?
  5. Could the polynomial be expressed in a non-factored form?

Tip: Remember that each root’s multiplicity affects the graph’s behavior at that root – higher multiplicities cause the graph to “bounce” off the axis rather than cross it.

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Math Problem Analysis

Mathematical Concepts

Polynomial Functions
Roots and Multiplicities
Factored Form

Formulas

Polynomial equation in factored form: P(x) = a(x - r1)^m1(x - r2)^m2...

Theorems

Fundamental Theorem of Algebra

Suitable Grade Level

Grades 10-12