**13.1 Graphs of Functions**

**13.1.1 Functions**

**1.**

**Function**is a

**relationship**that expresses a variable (dependent) in terms of another variable (independent).

**2.**

*y*is a

**function**of

*x*if and only if

**every value of**.

*x*corresponds to only one value of*y***13.1.2**

**Graphs of Functions**

**1.**

**A graph of function**is a representation of the function as one or more lines on a coordinate plane.

*Example:***When drawing graphs of functions, it is best to observe these few points:**

2.

2.

· choose suitable scales for both axes.

· use at least three points to draw a straight line to ensure accuracy.

· use at least five points to draw a curve to ensure accuracy.