In Algebra what exactly is a function?

a function is an expression that generates a value when an input is given.

For instance, the function x^2, when given 3 for x as input, generates 9, and nine can only be generated if 3 is imputed.

Here are some definitions of functions, in math talk.
http://www.cs.odu.edu/~toida/nerzic/content/function/definitions.html

In algebra, a function is a relation between a set of inputs (also called the domain) and a set of outputs (also called the range) in such a way that each input is associated with exactly one output. Essentially, it assigns each input value to only one output value.

Formally, a function can be represented as f(x), where 'x' represents the input value, and f(x) represents the corresponding output value. The function describes how the input values are transformed or mapped to the output values.

In simpler terms, think of a function as a machine that takes an input, performs some operations, and produces an output. Each input has a unique output, and the same input will always produce the same output when the function is applied.

A function can be represented in various ways, such as through equations, graphs, tables, or verbal descriptions. It is an essential concept in algebra and is widely used in various mathematical and real-world applications.

In Algebra, a function is a rule that maps input values (usually called the "input" or "independent variable") to output values (usually called the "output" or "dependent variable"). It represents a relationship between two sets of values, where each input value produces a unique output value.

To understand functions better, let's break down their components:

1. Input: This is the value that you plug into the function. It can be any element from a specified set, often represented by the variable "x".

2. Output: This is the value that the function produces as a result of the given input. It is usually represented by the variable "f(x)" or "y".

3. Rule: This is the mathematical operation or relationship that defines how the input is transformed into an output. It could involve basic arithmetic operations (addition, subtraction, multiplication, division) or more complex operations (exponents, logarithms, trigonometric functions).

For a function to be well-defined, each input value should correspond to exactly one output value. In other words, the mapping should be unambiguous. If an input value produces different output values or vice versa, it violates the function definition.

To determine whether a relationship is a function, you can use some common methods:

1. Vertical Line Test: Plot the points on a graph and draw vertical lines through them. If any vertical line intersects the graph at more than one point, the relationship is not a function. Otherwise, if each vertical line intersects at most one point, it is a function.

2. Mapping Diagram: List the input and output values and make sure each input maps to only one output.

3. Algebraic Notation: If the relationship can be expressed algebraically as an equation, make sure that for any given value of the input, there is only one corresponding value for the output.

Understanding functions is essential in algebra as they form the foundation for various concepts and calculations in mathematics. They have numerous applications in real-world problems and are extensively used in fields like physics, economics, and engineering.