Question

Determine whether the function is even, odd, or neither. $$ f(x)=2 x^{3}-3 x+1 $$

Short answer

The function \(f(x) = 2x^3 - 3x + 1\) is neither even nor odd, as \(f(-x) \neq f(x)\) and \(f(-x) \neq -f(x)\).

Step-by-step solution

Test for even function

To test if the given function is even, we need to find \(f(-x)\) and compare it with \(f(x)\). Let's find out \(f(-x)\): \[f(-x) = 2(-x)^3 - 3(-x) + 1\] \[f(-x) = -2x^3 + 3x + 1\] Now, let's compare \(f(x)\) and \(f(-x)\): \[f(x) = 2x^3 - 3x + 1\] \[f(-x) = -2x^3 + 3x + 1\] Thus, \(f(-x) \neq f(x)\). Therefore, the function is not even.

Test for odd function

In this step, we will test if the given function is odd by finding \(f(-x)\) again and comparing it with \(-f(x)\). We have already found \(f(-x)\) in the previous step: \[f(-x) = -2x^3 + 3x + 1\] Now, let's find \(-f(x)\): \[-f(x) = -(2x^3 - 3x + 1)\] \[-f(x) = -2x^3 + 3x - 1\] Now, let's compare \(-f(x)\) and \(f(-x)\): \[-f(x) = -2x^3 + 3x - 1\] \[f(-x) = -2x^3 + 3x + 1\] Thus, \(f(-x) \neq -f(x)\). Therefore, the function is not odd. Since the function is neither even nor odd, the answer is that the function is neither.

Key concepts

Algebraic Functions

In the realm of mathematics, an algebraic function is a type of function that can be expressed using polynomial equations of one or more variables. What sets these functions apart is the fact that they only involve operations that are foundational to algebra: addition, subtraction, multiplication, division, and taking roots. For example, the function given in the exercise,

\( f(x) = 2x^3 - 3x + 1 \),

is an algebraic function as it is made up of a polynomial equation in the variable \( x \). Algebraic functions are instrumental in numerous fields of study because they are relatively straightforward to work with and can be used to model a variety of real-world situations.

Symmetry in Functions

Symmetry in functions is a fundamental concept that helps to classify functions into even, odd, or neither based on their graphical representations. This symmetry is about the origin, or the y-axis, of the function's graph.

Even functions are symmetric about the y-axis. This means that if you fold the function's graph along the y-axis, the two halves would match perfectly. The algebraic test for even functions is that \( f(-x) = f(x) \) for all \( x \) in the function's domain.

Odd functions, on the other hand, are symmetric about the origin. If you rotate the graph of an odd function 180 degrees around the origin, it will look the same. The algebraic test for odd functions is that \( f(-x) = -f(x) \) for all \( x \) in the function's domain.

In our exercise, the function \( f(x) = 2x^3 - 3x + 1 \) does not pass either test, demonstrating that it does not possess symmetry about the y-axis or the origin, hence it is classified as neither even nor odd.

Polynomial Functions

Polynomial functions are a special class of algebraic functions defined by equations that involve only non-negative integer powers of the variable. These functions are expressed in the form

\( f(x) = a_nx^n + a_{n-1}x^{n-1} + \.\.\. + a_1x + a_0 \),

where \( a_n, a_{n-1}, ..., a_1, a_0 \) are coefficients and \( a_n \) is non-zero. The highest power of \( x \), denoted by \( n \), represents the degree of the polynomial.

Polynomial functions can be simple, like linear or quadratic equations, or more complex with higher degrees. They are particularly useful in mathematical modeling because they can smoothly approximate a wide range of phenomena. In our exercise, the function \( f(x) = 2x^3 - 3x + 1 \) is a third-degree polynomial function. Its highest power, \( x^3 \), indicates it is a cubic polynomial, which gives it certain characteristics in terms of growth and end behavior.