Power Function

Definition

A power function is a mathematical function that involves raising a variable to a constant power. Power functions are characterized by an independent variable raised to a fixed exponent, and they exhibit distinct patterns of growth or decay depending on the value of the exponent.

5 Must Know Facts For Your Next Test

1. The general form of a power function is $f(x) = ax^b$, where $a$ is the coefficient and $b$ is the exponent.
2. The value of the exponent $b$ determines the behavior of the power function, with $b > 0$ resulting in growth, $b < 0$ resulting in decay, and $b = 0$ resulting in a constant function.
3. Power functions can be used to model a wide range of real-world phenomena, such as population growth, radioactive decay, and the relationship between force and distance in physics.
4. The inverse of a power function is also a power function, with the exponent being the reciprocal of the original exponent.
5. Polynomial functions are a special case of power functions where the exponent is a positive integer, and they can be used to model a variety of linear, quadratic, and higher-order relationships.

Review Questions

• Explain how the value of the exponent in a power function affects the behavior of the function.
  • The value of the exponent $b$ in a power function $f(x) = ax^b$ determines the behavior of the function. When $b > 0$, the function exhibits growth, as the output increases with increasing input. When $b < 0$, the function exhibits decay, as the output decreases with increasing input. When $b = 0$, the function becomes a constant function, where the output is independent of the input.
• Describe the relationship between power functions and inverse functions, and how this relationship can be used to solve problems.
  • The inverse of a power function is also a power function, with the exponent being the reciprocal of the original exponent. This means that if $f(x) = ax^b$, then the inverse function $f^{-1}(x) = x^{1/b}/a$. This relationship can be used to solve problems involving the inverse of a power function, such as finding the input value given the output value, or determining the appropriate exponent to model a specific relationship.
• Analyze how power functions and polynomial functions are related, and explain how this relationship can be used to model real-world phenomena.
  • Polynomial functions are a special case of power functions, where the exponent is a positive integer. This means that power functions can be used to model a wider range of relationships, including those that cannot be accurately represented by polynomial functions. By understanding the properties of power functions and their relationship to polynomial functions, you can select the appropriate model to describe and predict real-world phenomena, such as population growth, radioactive decay, and the behavior of physical systems.

Related terms

Exponential Function: An exponential function is a special type of power function where the independent variable is the exponent, resulting in rapid growth or decay.

Polynomial Function: A polynomial function is a power function where the exponent is a positive integer, and the function can be expressed as a sum of terms with different powers of the independent variable.

Inverse Function: The inverse function of a power function reverses the relationship between the input and output, allowing the input to be determined from the output.