This week, we learned Relations and Functions Lesson #2~#9, I think this is a fun but very hard unit. Because there are many new proper nouns and the need to remember 😂.

Relation:A relation is a set of inputs and outputs, often written as ordered pairs (input, output)

Functions:A function is a relation in which each input has only one output.

When representing a relation, we often regard the values of the independent variable  as the input and the values of the dependent variable as the output.

The input values make up the domain of the relation ,and the output values make up the range of the relation.

The domain of a relation is the set of all possible values which can be used for the input of the independent variable(x)

The range of a relation is the set of all possible values of the output of the dependent variable.(y)

The following is a question I made when I first started to do a question(How to answer it is also written on the paper)