Evaluating the Composition of the Function and Its Inverse

Oct 13, 2025 by wbrum.org 84 views

Introduction

In mathematics, functions and their inverses play a crucial role in problem-solving. A function is a relation between a set of inputs (called the domain) and a set of possible outputs (called the range). The inverse of a function is a relation that undoes the action of the original function. In this article, we will use the given function $f(x)=\frac{1}{2} x$ and its inverse $f^{-1}(x)=2 x$ to solve three problems.

Problem 1: Evaluating the Function at a Given Input

The first problem asks us to evaluate the function $f(x)$ at $x=2$ . To do this, we simply substitute $x=2$ into the function $f(x)=\frac{1}{2} x$ .

Evaluating the Function at x=2

$f(2) = \frac{1}{2} \cdot 2$

$f(2) = 1$

Therefore, the value of the function $f(x)$ at $x=2$ is $1$ .

Problem 2: Evaluating the Inverse Function at a Given Input

The second problem asks us to evaluate the inverse function $f^{-1}(x)$ at $x=1$ . To do this, we simply substitute $x=1$ into the inverse function $f^{-1}(x)=2 x$ .

Evaluating the Inverse Function at x=1

$f^{-1}(1) = 2 \cdot 1$

$f^{-1}(1) = 2$

Therefore, the value of the inverse function $f^{-1}(x)$ at $x=1$ is $2$ .

Problem 3: Evaluating the Composition of the Function and Its Inverse

The third problem asks us to evaluate the composition of the function $f(x)$ and its inverse $f^{-1}(x)$ at $x=2$ . To do this, we first evaluate the function $f(x)$ at $x=2$ , and then evaluate the inverse function $f^{-1}(x)$ at the result.

Evaluating the Composition of the Function and Its Inverse

$f(2) = 1$

$f^{-1}(f(2)) = f^{-1}(1)$

$f^{-1}(f(2)) = 2$

Therefore, the value of the composition of the function $f(x)$ and its inverse $f^{-1}(x)$ at $x=2$ is $2$ .

Conclusion

In this article, we used the given function $f(x)=\frac{1}{2} x$ and its inverse $f^{-1}(x)=2 x$ to solve three problems. We evaluated the function at a given input, evaluated the inverse function at a given input, and evaluated the composition of the function and its inverse. The results show that the function and its inverse are indeed inverses of each other, and that they can be used to solve problems in a straightforward and efficient manner.

Key Takeaways

The function $f(x)=\frac{1}{2} x$ and its inverse $f^{-1}(x)=2 x$ are inverses of each other.
The function $f(x)$ can be evaluated at a given input by substituting the input into the function.
The inverse function $f^{-1}(x)$ can be evaluated at a given input by substituting the input into the inverse function.
The composition of the function $f(x)$ and its inverse $f^{-1}(x)$ can be evaluated by first evaluating the function at a given input, and then evaluating the inverse function at the result.

Q: What is a function?

A: A function is a relation between a set of inputs (called the domain) and a set of possible outputs (called the range). It is a way of describing a relationship between two variables.

Q: What is an inverse function?

A: An inverse function is a relation that undoes the action of the original function. It is a way of reversing the relationship between the input and output variables.

Q: How do I find the inverse of a function?

A: To find the inverse of a function, you need to swap the x and y variables and then solve for y. This will give you the inverse function.

Q: What is the difference between a function and its inverse?

A: The main difference between a function and its inverse is that the function takes an input and produces an output, while the inverse function takes the output and produces the input.

Q: Can a function have more than one inverse?

A: No, a function can only have one inverse. If a function has more than one inverse, it is not a one-to-one function.

Q: How do I know if a function is one-to-one?

A: A function is one-to-one if it passes the horizontal line test. This means that no horizontal line intersects the graph of the function more than once.

Q: What is the significance of the inverse of a function?

A: The inverse of a function is significant because it allows us to solve equations and inequalities involving the function. It also helps us to understand the behavior of the function and its graph.

Q: Can I use the inverse of a function to solve equations?

A: Yes, you can use the inverse of a function to solve equations. To do this, you need to substitute the inverse function into the equation and then solve for the variable.

Q: How do I use the inverse of a function to solve equations?

A: To use the inverse of a function to solve equations, you need to follow these steps:

Find the inverse of the function.
Substitute the inverse function into the equation.
Solve for the variable.

Q: What are some common applications of functions and their inverses?

A: Functions and their inverses have many common applications in mathematics, science, and engineering. Some examples include:

Modeling population growth and decline
Describing the motion of objects
Analyzing data and making predictions
Solving optimization problems

Q: How do I choose the right function to model a real-world problem?

A: To choose the right function to model a real-world problem, you need to consider the following factors:

The shape of the data
The rate of change of the data
The type of relationship between the variables

Q: What are some common types of functions?

A: Some common types of functions include:

Linear functions
Quadratic functions
Polynomial functions
Rational functions
Trigonometric functions

Q: How do I graph a function?

A: To graph a function, you need to follow these steps:

Find the x-intercepts of the function.
Find the y-intercepts of the function.
Plot the points on a coordinate plane.
Draw a smooth curve through the points.

Q: What are some common graphing techniques?

A: Some common graphing techniques include:

Plotting points
Drawing smooth curves
Using graph paper
Using technology to graph functions

Q: How do I use technology to graph functions?

A: To use technology to graph functions, you need to follow these steps:

Choose a graphing software or app.
Enter the function into the software or app.
Adjust the settings as needed.
View the graph.

Q: What are some common mistakes to avoid when graphing functions?

A: Some common mistakes to avoid when graphing functions include:

Plotting points incorrectly
Drawing smooth curves incorrectly
Using the wrong graphing software or app
Not adjusting the settings correctly