Section 25 What Are Graphs

1
Section 2-5What Are Graphs?

• October 22, 2009

2
What Is a Graph?

• A graph is a mathematical diagram that shows
• one variable (dependent) on the y (vertical) axis
• a second variable (independent) on the x
  (horizontal) axis.

3
2.1 Reading a graph

• A graph is a simple form of model that connects
  two or more variables.
• Scientists use models to make and test
  predictions.

4
(No Transcript)
5
Kinds of Relationships

• Two variables may have
• a strong relationship,
• a weak relationship,
• or no relationship at all.

6
Direct Relationships

• In a direct relationship, when one variable
  increases, the other also increases.
• This is also called a linear relationship.

7
Inverse Relationships

• In an inverse relationship, when one variable
  increases, the other decreases.

8
2.1 Complex Relationships

• Some relationships are neither direct nor
  inverse.
• This graph shows a non-linear relationship.

9
Linear and Non-Linear Graphs

• Linear graphs go in a straight line.
• They represent relationships with the formula ykx

10
Non-Linear Graphs

• Non-linear graphs go in curves
• They usually have formulas like ykx2

11
(No Transcript)