# Basics of Functions

Published on: by Chegg

## Introduction

In this article, we will explore the basics of functions by solving examples and understanding how to find the domain of functions. The concepts discussed here will help you understand functions better and apply them to various math problems.

## Example of evaluating a function at specific values

To evaluate a function at specific values, we must first understand the basics of functions. In the example provided, the function is given as f(x) = (2 - x)/(2 + x). We are tasked with computing f(1), f(2), and f(a + 2).

To compute f(1), we substitute x with 1 in the function, giving us (2 - 1)/(2 + 1) = 1/3. This means that the point (1, 1/3) lies on the graph of the function. Similarly, evaluating f(2) results in (2 - 2)/(2 + 2) = 0/4 = 0, indicating that the point (2, 0) is on the graph.

Moving on to f(a + 2), we replace x with (a + 2) in the function. Simplifying further yields (-a)/(a + 4). This implies that the point (a + 2, -a/(a + 4)) falls on the graph.

In another example provided, we are asked to determine the domain of two functions. For the function f(x) = 3x/(x^2 - 4), the domain consists of all real numbers except x = ±2. This is due to the function becoming undefined when the denominator is zero. On the other hand, for the function g(t) = √(t - 3), the domain includes all t greater than or equal to 3, as we cannot take the square root of a negative number.

Understanding how to evaluate functions at specific values and determine their domains is crucial in mathematics. By following the steps outlined in the examples, we can accurately calculate function values and identify valid input ranges for functions.

## Understanding ordered pairs and graphing functions

Understanding ordered pairs and graphing functions is a fundamental concept in mathematics. When dealing with functions, it is important to understand how to evaluate ordered pairs and graph them accordingly. In the example provided by the math sorcerer, the function f(x) = (2 - x)/(2 + x) was used to demonstrate how to compute F(1), F(2), and F(a + 2).

For F(1), we substituted x with 1 in the function and computed the result as 1/3. This means the ordered pair (1, 1/3) is on the graph of the function. Similarly, for F(2), the result was 0, indicating that the ordered pair (2, 0) is on the graph. In the case of F(a + 2), the result was -a/(a + 4), indicating that the point (a + 2, -a/(a + 4)) is on the graph.

Additionally, finding the domain of functions is crucial in determining the set of all x values that can be plugged into the function without causing any issues. In the examples provided by the math sorcerer, the domain for f(x) = 3x/(x^2 - 4) was found to be all real numbers except x = ±2, and the domain for g(t) = √(t - 3) was found to be t ≥ 3.

Understanding how to evaluate ordered pairs and determine the domain of functions is essential for graphing functions accurately and analyzing their behavior. By mastering these concepts, students can enhance their problem-solving skills and grasp the fundamentals of functions in mathematics. It is vital to practice calculating ordered pairs and domains to strengthen mathematical knowledge and improve graphing skills.

## Finding the domain of functions with fractions

When dealing with functions that involve fractions, it is important to find the domain of the function to ensure that it is well-defined. In the given example, the function is f(x) = (2 - x) / (2 + x). To compute values like f(1), f(2), and f(a + 2), we substitute the given values into the function and simplify the expression accordingly. For example, f(1) simplifies to 1/3, indicating that the point (1, 1/3) lies on the graph of the function. Similarly, f(2) simplifies to 0, implying that the point (2, 0) is on the graph.

Moving on to finding the domain of a function involving fractions, such as f(x) = 3x / (x^2 - 4), we need to identify values of x that would make the denominator zero. In this case, setting the denominator equal to zero yields x = ±2. Therefore, the domain of this function is all real numbers except for x = ±2. In interval notation, this would be represented as (-∞, -2) ∪ (-2, 2) ∪ (2, ∞).

Another example involves a function with a square root, such as g(t) = √(t - 3). To ensure that the function yields real values, we set the expression inside the square root to be greater than or equal to zero. Solving for t, we find that t ≥ 3, indicating that the domain of this function is all values of t greater than or equal to 3, represented in interval notation as [3, ∞). By understanding how to find the domain of functions with fractions and square roots, we ensure that the functions are well-defined and provide meaningful results.

## Finding the domain of functions with square roots

Finding the domain of functions with square roots is an essential concept in mathematics. The domain of a function refers to the set of all possible values that the input variable, in this case, "x" or "T", can take while still producing a valid output. In the examples provided by the Math Sorcerer, we see how to determine the domain of functions involving fractions and square roots.

When dealing with fractions, such as in the function f(x) = 3x / (x^2 - 4), we need to identify the values of x that would make the denominator zero. In this case, setting the denominator equal to zero reveals that x cannot be equal to plus or minus 2. Therefore, the domain of the function is all real numbers except x equals plus or minus 2. This can be represented on a number line and in interval notation to clearly show the range of valid inputs for the function.

On the other hand, when working with square roots, as seen in the function T - 3, we need to ensure that the expression inside the square root is greater than or equal to zero to obtain a real number output. By setting T - 3 greater than or equal to zero, we find that T must be greater than or equal to 3 for the function to be defined. This information can also be illustrated on a number line and written in interval notation to indicate the domain of the function.

Understanding how to find the domain of functions with square roots is crucial for solving mathematical problems and analyzing functions accurately. By following the steps outlined by the Math Sorcerer and applying them to various types of functions, you can enhance your problem-solving skills and mathematical knowledge.

## Highlights

- Explaining how to evaluate functions at specific values
- Illustrating the concept of ordered pairs on graphs
- Demonstrating how to find the domain of functions with fractions
- Explaining the process of finding the domain of functions with square roots
- Providing useful tips and insights for solving math problems involving functions

## FAQ

**Q: What is the significance of evaluating functions at specific values?**

A: Evaluating functions at specific values helps us understand how the function behaves for different inputs. It allows us to calculate the output of the function at those values and analyze the relationship between the input and output.

**Q: How do ordered pairs relate to graphing functions?**

A: Ordered pairs represent points on the graph of a function where the x-coordinate corresponds to the input value and the y-coordinate corresponds to the output value. Knowing ordered pairs helps us visualize the function graphically and study its behavior.

**Q: Why is finding the domain of functions important?**

A: Finding the domain of a function is crucial as it determines the set of valid input values for the function. Understanding the domain helps us avoid mathematical errors and ensures that we can accurately analyze and interpret the function.

**Q: How does the domain of a function with fractions affect its behavior?**

A: The domain of a function with fractions is restricted by the values that make the denominator nonzero. Identifying these values helps us avoid division by zero and ensures that the function is well-defined for all valid inputs.

**Q: Why is setting the expression inside a square root greater than or equal to zero important for finding the domain?**

A: Setting the expression inside a square root greater than or equal to zero ensures that the square root function produces real numbers. By restricting the input values to satisfy this condition, we guarantee that the function outputs meaningful results without encountering complex numbers.