Useful Article : Relation and Function 1

Relations
A Relation is a rule that gives one or more outputs for every valid input. The input is the Independent Variable, and x is often used as the input variable. The output is the dependent variable, and y is often used as the output variable. The output depends on the input value.

The relation may be described as:

1. Set of ordered pairs: The {} represents the set, and (,) represents the ordered pair. The ordered pair means (1, 2) and (2, 1) are different. The first element in the ordered pair is the input, and the second element is the output.Example: { (-2, 1), (0, 3), (2, 1), (-1, 5) }
2. An equation: An equation that relates the input and output. Examples: y=x2+2x=-1 x2+y2=25
3. A Rule/ description in words: A rule that relates the input and the output. Examples: The output is three times the input; the width of the rectangle is 5 units more than the length.
4. An arrow diagram:
5. A continuous graph:
6. A scatter plot: It is also known as a discrete graph.
7. An input/output diagram
8. A table: