Problem 51

Question

State whether the function is odd, even, or neither. $$g(x)=x(x-1)$$

Step-by-Step Solution

Verified
Answer
The function \(g(x)=x(x-1)\) is neither odd nor even.
1Step 1: Find g(-x)
First, plug the reciprocal value (-x) into the function \(g(x) = x(x - 1)\) to get \(g(-x) = -x(-x - 1)\) which simplifies to \(g(-x) = -x^2 + x\).
2Step 2: Compare g(-x) and g(x)
Then, compare g(-x) which is \(-x^2 + x\) and g(x) which is \(x^2 - x\). It's easy to see that g(-x) ≠ g(x) and g(-x) ≠ -g(x). This means the function is neither even nor odd.

Key Concepts

Function AnalysisPolynomial FunctionsSymmetry in Functions
Function Analysis
Function analysis is an essential approach in mathematics, focusing on breaking down functions to understand their properties and behaviors. When analyzing functions, one often needs to determine if they are even, odd, or neither. Let's explore what this means.
For even functions, the key property is that they remain unchanged when you substitute \(-x\) for \x\. Mathematically, this is defined as \(f(-x) = f(x)\). Imagining the graph of such functions, you’ll notice symmetry about the y-axis.
Odd functions, on the other hand, demonstrate a reflection symmetry over the origin. This requires that \(f(-x) = -f(x)\). If the graph is rotated 180 degrees around the origin, it appears identical.
However, not every function will fit neatly into these categories. When a function is neither even nor odd, neither of these symmetry properties holds, meaning \(f(-x) \eq f(x)\) and \(f(-x) \eq -f(x)\). In our exercise with \(g(x) = x(x - 1)\), by performing these checks, we observed it to be neither even nor odd.
Polynomial Functions
Polynomial functions are a crucial concept in algebra, known for their versatility and wide range of applications. Generally, a polynomial function is expressed as a sum of powers of \x\, each multiplied by a coefficient. Examples include linear polynomials like \(ax + b\) and quadratics such as \(ax^2 + bx + c\).
The specific function from the exercise, \(g(x) = x(x - 1)\), is a quadratic polynomial. Understanding it involves recognizing that it can be expanded and rewritten as \(g(x) = x^2 - x\).
Polynomial functions are defined for all real numbers and exhibit unique characteristics depending on their degree. Their graphs can range from simple lines to curves that open in different directions based on their highest-degree term. For example, a quadratic polynomial, like the one in our problem, generally forms a parabola. By exploring such properties, we can gain deeper insights into how polynomial functions behave.
Symmetry in Functions
Symmetry in functions helps simplify complex problems by revealing balanced properties. Understanding symmetry can play a pivotal role in analyzing and solving mathematical problems.
Symmetry in functions is primarily about determining whether a function looks the same, either across the y-axis or around the origin. Recognizing symmetry in polynomial functions adds a valuable layer of understanding. For instance, even and odd functions exhibit specific types of symmetry:
  • Even functions: Symmetric about the y-axis.
  • Odd functions: Symmetric about the origin.
These symmetries can be observed by substituting negative values into the function and checking equivalence.
The function \(g(x) = x(x - 1)\) from our exercise shows that neither y-axis nor origin symmetry exists. By breaking it into \(g(-x) = -x^2 + x\) and comparing with \(g(x)\), we found neither even nor odd symmetry, highlighting its unique symmetry profile.