Math Problem Statement

f(x) = x2(x – a)2(x – b)4(x – c)

f(x) = x3(x – a)3(x – b)(x – c)2

f(x) = x4(x – a)(x – b)3(x – c)3

f(x) = (x – a)2(x – b)(x – c)6

Let a, b, and c be real numbers where a ≠ b ≠ c ≠ 0. Which of the following functions could represent the graph below? f(x) = x^2(x - a)^2(x - b)^4(x - c) f(x) = x^3(x - a)^3(x - b)(x - c)^2 f(x) = x^4(x - a)(x - b)^3(x - c)^3 f(x) = (x - a)^2(x - b)(x - c)^6

Solution

To determine which function could represent the graph, let’s analyze the key characteristics of the graph, especially the zeroes, multiplicities, and general behavior.

Observations from the Graph

  1. Roots: The graph crosses the x-axis at least three distinct points, indicating at least three distinct roots.
  2. Multiplicity of Roots: The graph shows some roots with an odd multiplicity (it crosses the x-axis) and some with an even multiplicity (it touches the x-axis without crossing it).
  3. Degree of Polynomial: The overall shape suggests a higher degree polynomial with positive leading behavior (as xx \to \infty, f(x)f(x) \to \infty).

Analyzing Each Option

Let’s break down each given function to match these characteristics:

  1. Option 1: f(x)=x2(xa)2(xb)4(xc)f(x) = x^2(x - a)^2(x - b)^4(x - c)

    • Degree: 2+2+4+1=92 + 2 + 4 + 1 = 9
    • Roots: x=0,x=a,x=b,x=cx = 0, x = a, x = b, x = c
    • The graph of a degree-9 polynomial would generally end with opposite signs as x±x \to \pm \infty. However, this graph ends with both ends up, so this option may not fit.
  2. Option 2: f(x)=x3(xa)3(xb)(xc)2f(x) = x^3(x - a)^3(x - b)(x - c)^2

    • Degree: 3+3+1+2=93 + 3 + 1 + 2 = 9
    • Roots: x=0,x=a,x=b,x=cx = 0, x = a, x = b, x = c
    • Similar to Option 1, this has a degree-9, but with a similar issue of sign behavior at both ends.
  3. Option 3: f(x)=x4(xa)(xb)3(xc)3f(x) = x^4(x - a)(x - b)^3(x - c)^3

    • Degree: 4+1+3+3=114 + 1 + 3 + 3 = 11
    • Roots: x=0,x=a,x=b,x=cx = 0, x = a, x = b, x = c
    • Degree-11 would also show opposite end behavior, which doesn’t match.
  4. Option 4: f(x)=(xa)2(xb)(xc)6f(x) = (x - a)^2(x - b)(x - c)^6

    • Degree: 2+1+6=92 + 1 + 6 = 9
    • Roots: x=a,x=b,x=cx = a, x = b, x = c only, no x=0x = 0.
    • Matches an odd multiplicity for root

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Math Problem Analysis

Mathematical Concepts

Polynomial Functions
Roots and Multiplicity
End Behavior of Polynomials

Formulas

General form of a polynomial function

Theorems

Multiplicity Theorem for Polynomial Roots

Suitable Grade Level

Grades 11-12