Finding Composite Functions

Oct 13, 2025 by wbrum.org 93 views

Introduction

In this article, we will explore the concept of composite functions and their domains. We will be given two functions, $f(x)=\sqrt{3x-2}$ and $g(x)=\frac{1}{x}$ , and we will need to find the composite functions $(f+g)(x)$ , $(f-g)(x)$ , $(fg)(x)$ , and $\left(\frac{f}{g}\right)(x)$ . Additionally, we will determine the domain of each composite function.

Finding Composite Functions

To find the composite functions, we will use the definitions of function addition, subtraction, multiplication, and division.

Function Addition

The function addition is defined as $(f+g)(x) = f(x) + g(x)$ . In this case, we have:

$(f+g)(x) = f(x) + g(x) = \sqrt{3x-2} + \frac{1}{x}$

Function Subtraction

The function subtraction is defined as $(f-g)(x) = f(x) - g(x)$ . In this case, we have:

$(f-g)(x) = f(x) - g(x) = \sqrt{3x-2} - \frac{1}{x}$

Function Multiplication

The function multiplication is defined as $(fg)(x) = f(x) \cdot g(x)$ . In this case, we have:

$(fg)(x) = f(x) \cdot g(x) = \sqrt{3x-2} \cdot \frac{1}{x} = \frac{\sqrt{3x-2}}{x}$

Function Division

The function division is defined as $\left(\frac{f}{g}\right)(x) = \frac{f(x)}{g(x)}$ . In this case, we have:

$\left(\frac{f}{g}\right)(x) = \frac{f(x)}{g(x)} = \frac{\sqrt{3x-2}}{\frac{1}{x}} = \sqrt{3x-2} \cdot x = x\sqrt{3x-2}$

Determining Domains

To determine the domain of each composite function, we need to consider the restrictions on the variables.

Domain of $(f+g)(x)$

The domain of $(f+g)(x)$ is the set of all values of $x$ for which both $\sqrt{3x-2}$ and $\frac{1}{x}$ are defined. Since $\sqrt{3x-2}$ is defined for all $x \geq \frac{2}{3}$ , and $\frac{1}{x}$ is defined for all $x \neq 0$ , the domain of $(f+g)(x)$ is $x \geq \frac{2}{3}$ and $x \neq 0$ .

Domain of $(f-g)(x)$

The domain of $(f-g)(x)$ is the set of all values of $x$ for which both $\sqrt{3x-2}$ and $\frac{1}{x}$ are defined. Since $\sqrt{3x-2}$ is defined for all $x \geq \frac{2}{3}$ , and $\frac{1}{x}$ is defined for all $x \neq 0$ , the domain of $(f-g)(x)$ is $x \geq \frac{2}{3}$ and $x \neq 0$ .

Domain of $(fg)(x)$

The domain of $(fg)(x)$ is the set of all values of $x$ for which both $\sqrt{3x-2}$ and $\frac{1}{x}$ are defined. Since $\sqrt{3x-2}$ is defined for all $x \geq \frac{2}{3}$ , and $\frac{1}{x}$ is defined for all $x \neq 0$ , the domain of $(fg)(x)$ is $x \geq \frac{2}{3}$ and $x \neq 0$ .

Domain of $\left(\frac{f}{g}\right)(x)$

The domain of $\left(\frac{f}{g}\right)(x)$ is the set of all values of $x$ for which both $\sqrt{3x-2}$ and $\frac{1}{x}$ are defined. Since $\sqrt{3x-2}$ is defined for all $x \geq \frac{2}{3}$ , and $\frac{1}{x}$ is defined for all $x \neq 0$ , the domain of $\left(\frac{f}{g}\right)(x)$ is $x \geq \frac{2}{3}$ and $x \neq 0$ .

Conclusion

In this article, we have found the composite functions $(f+g)(x)$ , $(f-g)(x)$ , $(fg)(x)$ , and $\left(\frac{f}{g}\right)(x)$ , and determined their domains. We have seen that the domain of each composite function is the set of all values of $x$ for which both $\sqrt{3x-2}$ and $\frac{1}{x}$ are defined.

Introduction

In our previous article, we explored the concept of composite functions and their domains. We found the composite functions $(f+g)(x)$ , $(f-g)(x)$ , $(fg)(x)$ , and $\left(\frac{f}{g}\right)(x)$ , and determined their domains. In this article, we will answer some frequently asked questions (FAQs) related to composite functions and domains.

Q&A

Q: What is the domain of $(f+g)(x)$ ?

A: The domain of $(f+g)(x)$ is the set of all values of $x$ for which both $\sqrt{3x-2}$ and $\frac{1}{x}$ are defined. Since $\sqrt{3x-2}$ is defined for all $x \geq \frac{2}{3}$ , and $\frac{1}{x}$ is defined for all $x \neq 0$ , the domain of $(f+g)(x)$ is $x \geq \frac{2}{3}$ and $x \neq 0$ .

Q: What is the domain of $(f-g)(x)$ ?

A: The domain of $(f-g)(x)$ is the set of all values of $x$ for which both $\sqrt{3x-2}$ and $\frac{1}{x}$ are defined. Since $\sqrt{3x-2}$ is defined for all $x \geq \frac{2}{3}$ , and $\frac{1}{x}$ is defined for all $x \neq 0$ , the domain of $(f-g)(x)$ is $x \geq \frac{2}{3}$ and $x \neq 0$ .

Q: What is the domain of $(fg)(x)$ ?

A: The domain of $(fg)(x)$ is the set of all values of $x$ for which both $\sqrt{3x-2}$ and $\frac{1}{x}$ are defined. Since $\sqrt{3x-2}$ is defined for all $x \geq \frac{2}{3}$ , and $\frac{1}{x}$ is defined for all $x \neq 0$ , the domain of $(fg)(x)$ is $x \geq \frac{2}{3}$ and $x \neq 0$ .

Q: What is the domain of $\left(\frac{f}{g}\right)(x)$ ?

A: The domain of $\left(\frac{f}{g}\right)(x)$ is the set of all values of $x$ for which both $\sqrt{3x-2}$ and $\frac{1}{x}$ are defined. Since $\sqrt{3x-2}$ is defined for all $x \geq \frac{2}{3}$ , and $\frac{1}{x}$ is defined for all $x \neq 0$ , the domain of $\left(\frac{f}{g}\right)(x)$ is $x \geq \frac{2}{3}$ and $x \neq 0$ .

Q: How do I find the composite functions $(f+g)(x)$ , $(f-g)(x)$ , $(fg)(x)$ , and $\left(\frac{f}{g}\right)(x)$ ?

A: To find the composite functions, you can use the definitions of function addition, subtraction, multiplication, and division. For example, to find $(f+g)(x)$ , you can add $f(x)$ and $g(x)$ , which gives you $\sqrt{3x-2} + \frac{1}{x}$ .

Q: What are some common mistakes to avoid when working with composite functions?

A: Some common mistakes to avoid when working with composite functions include:

Not considering the domain of each function
Not using the correct definition of function addition, subtraction, multiplication, and division
Not simplifying the resulting expression
Not checking for any restrictions on the variables

Conclusion

In this article, we have answered some frequently asked questions (FAQs) related to composite functions and domains. We have seen that the domain of each composite function is the set of all values of $x$ for which both $\sqrt{3x-2}$ and $\frac{1}{x}$ are defined. We have also provided some tips on how to find the composite functions and avoid common mistakes.