Relation and function
Relation and function are two concepts in mathematics used to describe a connection between two sets of values.
A relation is a set of ordered pairs, typically expressed as (x, y), where x and y represent values from two sets. For example, {(1,2), (3,4), (2,5)} is a relation between set A={1,2,3} and set B={2,4,5}.
A function, on the other hand, is a special type of relation in which each value of the first set (called the domain) is associated with exactly one value in the second set (called the range). In other words, for each x in the domain, there is only one y in the range such that (x,y) is in the relation.
A common way to express a function is with the notation f(x), where f is the name of the function and x is the input value (or independent variable). For example, f(x) = x^2 is a function that takes an input value x and squares it to get the output value (or dependent variable) y.
Overall, relations and functions are important mathematical concepts that help us understand the relationships between different sets of values.