Finding the Domain of the Function

Oct 13, 2025 by wbrum.org 12 views

Introduction

In mathematics, functions are used to describe the relationship between two variables. The domain of a function is the set of all possible input values, while the range is the set of all possible output values. In this article, we will explore the domain and range of the function $f(x)=\frac{x^2+8x+7}{x+1}$ .

What is the Domain of a Function?

The domain of a function is the set of all possible input values. In other words, it is the set of all values of x for which the function is defined. To find the domain of a function, we need to identify any values of x that would make the function undefined.

Finding the Domain of the Function

The function $f(x)=\frac{x^2+8x+7}{x+1}$ is a rational function, which means it is a ratio of two polynomials. The function is undefined when the denominator is equal to zero, because division by zero is undefined.

To find the values of x that make the denominator equal to zero, we need to solve the equation $x+1=0$ . This equation has a single solution, which is $x=-1$ .

Therefore, the domain of the function is all real numbers except $x=-1$ . We can write this as:

D:\{x \in \mathbb{R} \mid x \neq -1\}

What is the Range of a Function?

The range of a function is the set of all possible output values. In other words, it is the set of all values of y that the function can produce.

Finding the Range of the Function

To find the range of the function, we need to consider the behavior of the function as x approaches positive and negative infinity.

As x approaches positive infinity, the function approaches positive infinity. This is because the numerator of the function is a quadratic expression that grows without bound as x increases.

As x approaches negative infinity, the function approaches negative infinity. This is because the numerator of the function is a quadratic expression that grows without bound as x decreases.

Therefore, the range of the function is all real numbers except zero. We can write this as:

R:\{y \in \mathbb{R} \mid y \neq 0\}

Conclusion

In conclusion, the domain of the function $f(x)=\frac{x^2+8x+7}{x+1}$ is all real numbers except $x=-1$ , and the range is all real numbers except zero.

Answer

The correct answer is:

A. $D:\{x \in \mathbb{R} \mid x \neq 1\} ; R:\{y \in \mathbb{R} \mid y \neq 0\}$

However, this is incorrect. The correct answer is:

A. $D:\{x \in \mathbb{R} \mid x \neq -1\} ; R:\{y \in \mathbb{R} \mid y \neq 0\}$

Final Answer

The final answer is:

A. $D:\{x \in \mathbb{R} \mid x \neq -1\} ; R:\{y \in \mathbb{R} \mid y \neq 0\}$