The function f(x) = 2x ( x + 2) (x - 1)² is a polynomial function that is not a power function.
Identification of functions.
A function f(x) is said to be defined if each set of input variables (domain) is assigned to a specific output variable (co-domain).
In the given function:
f(x) = 2x ( x + 2) (x - 1)²; we are to identify if the function is a power function, a polynomial function, or neither.
To do that, we need to solve the function by using the following steps.
f(x) = 2x ( x + 2) (x - 1)²
f(x) = (2x² + 4x ) (x² - 2x + 1)
f(x) = 2x⁴ - 4x³ + 2x² + 4x³ - 8x² + 4x
f(x) = 2x⁴ - 6x² + 4x
A power function takes the form
, thus we can't agree that the above function as a power function.
Similarly, a polynomial function can be expressed using the general formula:

Therefore, we can conclude that the function:
f(x) = 2x ( x + 2) (x - 1)² = 2x⁴ - 6x² + 4x is a polynomial function that is not a power function.