The range of numbers that can enter a function is known as its domain. Or, to put it another way, it is the range of x-values that you can use with any particular equation. The range refers to the set of feasible y-values. Simply follow these instructions to learn how to determine the domain of a function in several situations.
Table of Contents
Learning The Basics
- Learn The Meaning of The Domain
The set of input values that the function accepts to return a value is referred to as the domain. The domain, then, is the entire set of x-values that can be passed into a function to yield a y-value.
- Learn How to Identify The Domain of Different Functions
The ideal strategy for choosing a domain will depend on the type of function. The essential information regarding each category of function, which will be explained in the following section, is as follows:
- Without radicals or variables in the denominator, a polynomial function. All real numbers make up the domain for this kind of function.
- A formula where the denominator is a fraction with a variable. Set the bottom equal to zero and take the value of x you obtain from solving the equation out of consideration to determine the domain of this kind of function.
- A function that contains a variable inside a radical sign. Set the terms inside the radical sign to >0 and solve for the values that would work for x to determine the domain of this kind of function.
- A graph. See which values for x are appropriate by looking at the graph.
- A relationship between X and Y coordinates will be listed in this. You will just have a list of x coordinates for your domain.
- State The Domain Accurately
Although learning the correct notation for the domain is simple, it is crucial that you write it correctly to express the right response and receive full credit for your work on projects and tests.
How to Find The Domain of A Function?
Use the following procedures to determine a function’s domain:
Step 1: Check that the given function can include all real numbers by doing so first.
Next, determine if the denominator of the fraction and the denominator of the provided function are both non-zero real numbers in step two.
Step 3: Occasionally, a function’s domain is restricted, meaning that there are specific values that the function cannot be specified.
For example, the domain of a function f(x) = 2x + 1 is the set of all real numbers (R). However, the domain of the function f(x) = 1/ (2x + 1) is the set of all real numbers except -1/2.
Step 4: Sometimes the function is provided along with the interval at which it is defined. For example, f (x) = 2×2 + 3, -5 < x < 5. Here, the input values of x are between -5 and 5. As a result, the domain of f(x) is (-5, 5).
The group of numbers that are left after completing all the processes mentioned above are referred to as the domain of a function.
Let’s Discuss The Concept with The Help of Some Examples:
Example 1: Find The Domain and Range of A Function f(x) = x2 + 1
Given: f(x) = x2 + 1
We are aware that the set of all possible values for which a function can be defined is known as the domain of the function.
Here, the given function has no undefined values of x.
So, the domain is the set of all real numbers, for the given function
Thus, the Domain of f(x) = (-∞, ∞)
While the set of images of the elements in the domain is the range of a function
Let y = x2 + 1
x2 = y − 1
x = √(y − 1)
We know that a square root function is defined for non-negative values.
So, √(y − 1) ≥ 0
This is possible when y is greater than y ≥ 1.
Therefore, the range of f(x) is [1, ∞).
Example 2: Find The Domain of A Function f(x) = (2x + 1)/ (x2 − 4x + 3)
Given: f(x) = (2x + 1)/ (x2 − 4x + 3)
f(x) = (2x + 1)/ (x − 1)(x − 3)
We are aware that the set of all potential values for which a function can be defined is the function’s domain.
Here, the provided function is a rational function that is defined only for non-zero numbers of its denominator.
So, (x − 1)(x − 3) ≠ 0
x − 1 ≠ 0 and x − 3 ≠ 0
x ≠ 1 and x ≠ 3
Domain = R − {1, 3}
Hence, the domain of the given function is x ∈ R − {1, 3}.
Summing Up
We are sure that in this article, you’ll get to know complete details on how to find the domain of a function. To make the concept clear, we stated some examples. So, give this article a read for the clearance of the concept!
