Domain and Range of the Composition

Oct 13, 2025 by wbrum.org 103 views

Domain and Range of Functions: A Comprehensive Analysis

In mathematics, functions play a crucial role in modeling real-world phenomena. Understanding the domain and range of functions is essential in various fields, including algebra, calculus, and engineering. In this article, we will explore the domain and range of two given functions, ${ f(x) = x - 2 }$ and ${ g(x) = 7x^2 }$ . We will analyze each function separately and then compare their properties.

The domain of a function is the set of all possible input values (x-values) for which the function is defined. In other words, it is the set of all possible x-values that the function can accept without resulting in an undefined or imaginary output.

Domain of ${ f(x) = x - 2 }$

To find the domain of ${ f(x) = x - 2 }$ , we need to consider the possible values of x that make the function defined. Since the function is a linear equation, it is defined for all real numbers. Therefore, the domain of ${ f(x) = x - 2 }$ is the set of all real numbers, which can be represented as ${ (-\infty, \infty) }$ .

Domain of ${ g(x) = 7x^2 }$

The function ${ g(x) = 7x^2 }$ is a quadratic equation, and it is defined for all real numbers. However, we need to consider the possibility of negative values under the square root. Since the square of any real number is always non-negative, the function ${ g(x) = 7x^2 }$ is defined for all real numbers. Therefore, the domain of ${ g(x) = 7x^2 }$ is also the set of all real numbers, which can be represented as ${ (-\infty, \infty) }$ .

The range of a function is the set of all possible output values (y-values) that the function can produce for the given input values.

Range of ${ f(x) = x - 2 }$

To find the range of ${ f(x) = x - 2 }$ , we need to consider the possible values of y that the function can produce. Since the function is a linear equation, it can produce all real numbers. Therefore, the range of ${ f(x) = x - 2 }$ is the set of all real numbers, which can be represented as ${ (-\infty, \infty) }$ .

Range of ${ g(x) = 7x^2 }$

The function ${ g(x) = 7x^2 }$ is a quadratic equation, and it can produce all non-negative real numbers. Since the square of any real number is always non-negative, the function ${ g(x) = 7x^2 }$ can produce all non-negative real numbers. Therefore, the range of ${ g(x) = 7x^2 }$ is the set of all non-negative real numbers, which can be represented as ${ [0, \infty) }$ .

The composition of two functions ${ f }$ and ${ g }$ is defined as ${ (f \circ g)(x) = f(g(x)) }$ . In this case, we can find the composition of ${ f(x) = x - 2 }$ and ${ g(x) = 7x^2 }$ as follows:

${ (f \circ g)(x) = f(g(x)) = f(7x^2) = 7x^2 - 2 }$

Domain and Range of the Composition

To find the domain and range of the composition ${ (f \circ g)(x) = 7x^2 - 2 }$ , we need to consider the properties of the individual functions. Since the domain of ${ g(x) = 7x^2 }$ is the set of all real numbers, the domain of the composition ${ (f \circ g)(x) = 7x^2 - 2 }$ is also the set of all real numbers. Therefore, the domain of the composition is ${ (-\infty, \infty) }$ .

To find the range of the composition ${ (f \circ g)(x) = 7x^2 - 2 }$ , we need to consider the properties of the individual functions. Since the range of ${ g(x) = 7x^2 }$ is the set of all non-negative real numbers, the range of the composition ${ (f \circ g)(x) = 7x^2 - 2 }$ is also the set of all non-negative real numbers. Therefore, the range of the composition is ${ (-\infty, \infty) }$ .

In conclusion, we have analyzed the domain and range of two given functions, ${ f(x) = x - 2 }$ and ${ g(x) = 7x^2 }$ . We have found that the domain of both functions is the set of all real numbers, and the range of ${ f(x) = x - 2 }$ is the set of all real numbers, while the range of ${ g(x) = 7x^2 }$ is the set of all non-negative real numbers. We have also found that the composition of the two functions has a domain of all real numbers and a range of all non-negative real numbers.

[1] Thomas, G. B. (2018). Calculus and Analytic Geometry. Pearson Education.
[2] Larson, R. E. (2018). Calculus. Cengage Learning.
[3] Anton, H. (2018). Calculus: Early Transcendentals. John Wiley & Sons.

Domain: The set of all possible input values (x-values) for which the function is defined.
Range: The set of all possible output values (y-values) that the function can produce for the given input values.
Composition of functions: The combination of two functions ${ f }$ and ${ g }$ defined as ${ (f \circ g)(x) = f(g(x)) }$ .
Q&A: Domain and Range of Functions =====================================

In our previous article, we explored the domain and range of two given functions, ${ f(x) = x - 2 }$ and ${ g(x) = 7x^2 }$ . We analyzed each function separately and then compared their properties. In this article, we will answer some frequently asked questions related to the domain and range of functions.

Q: What is the domain of a function?

A: The domain of a function is the set of all possible input values (x-values) for which the function is defined.

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

A: To find the domain of a function, you need to consider the possible values of x that make the function defined. For example, if the function has a square root, you need to consider the possibility of negative values under the square root.

Q: What is the range of a function?

A: The range of a function is the set of all possible output values (y-values) that the function can produce for the given input values.

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

A: To find the range of a function, you need to consider the possible values of y that the function can produce. For example, if the function is a linear equation, it can produce all real numbers.

Q: What is the composition of functions?

A: The composition of two functions ${ f }$ and ${ g }$ is defined as ${ (f \circ g)(x) = f(g(x)) }$ .

Q: How do I find the domain and range of the composition of functions?

A: To find the domain and range of the composition of functions, you need to consider the properties of the individual functions. For example, if the domain of ${ g(x) = 7x^2 }$ is the set of all real numbers, the domain of the composition ${ (f \circ g)(x) = 7x^2 - 2 }$ is also the set of all real numbers.

Q: What are some common mistakes to avoid when finding the domain and range of functions?

A: Some common mistakes to avoid when finding the domain and range of functions include:

Not considering the possibility of negative values under the square root.
Not considering the possibility of division by zero.
Not considering the possibility of undefined values.

Q: How can I practice finding the domain and range of functions?

A: You can practice finding the domain and range of functions by working through examples and exercises. You can also use online resources, such as calculators and graphing software, to visualize the functions and their properties.

Q: What are some real-world applications of the domain and range of functions?

A: The domain and range of functions have many real-world applications, including:

Modeling population growth and decline.
Modeling the spread of diseases.
Modeling the behavior of electrical circuits.
Modeling the behavior of mechanical systems.

In conclusion, we have answered some frequently asked questions related to the domain and range of functions. We have discussed the importance of considering the properties of individual functions when finding the domain and range of the composition of functions. We have also highlighted some common mistakes to avoid and provided some real-world applications of the domain and range of functions.

[1] Thomas, G. B. (2018). Calculus and Analytic Geometry. Pearson Education.
[2] Larson, R. E. (2018). Calculus. Cengage Learning.
[3] Anton, H. (2018). Calculus: Early Transcendentals. John Wiley & Sons.

Domain: The set of all possible input values (x-values) for which the function is defined.
Range: The set of all possible output values (y-values) that the function can produce for the given input values.
Composition of functions: The combination of two functions ${ f }$ and ${ g }$ defined as ${ (f \circ g)(x) = f(g(x)) }$ .