Coordinate systems: 
They are two mutually perpendicular coordinate lines which intersect in the origin O on each line.

The four quadrants in a coordinate system:
Quadrant I is the area where a>0 and b>0.
Quadrant II is the area where a<0 and b>0.
Quadrant III is the area where a<0 and b<0.
Quadrant IV is the area where a>0 and b<0.

Distance: 
The distance between any two points is defined as:
.

Data sets:
The grouping or collection of similar or related data.

Subsets:
If A and B are sets and every element of A is also an element of B, then: A is a subset of B, denoted by.

Product of two data sets:
If S and T are sets, the product set of S and T will be denoted by , which satisfies

• .

Line:

A geometric figure formed by a point moving along a fixed direction and the reverse direction.

Slope of a line:
If and are arbitrary two points on the line, the slope can be calculated by
.

Midpoint of any two points:
The distance between two arbitrary points is given by
.

Flash Movie	Flash Game	Flash Card
Core Concept Tutorial	Problem Solving Drill	Review Cheat Sheet

This tutorial describes basic graphs of functions and how they are graphically represented in the Cartesian plane. The coordinate systems in two variables are introduced with the help of graphs.

Key concepts such as the midpoint, and the distance of between two points are discussed in this tutorial. The use of relations between two sets of points and their graphs is introduced so data can be graphically represented.

Specific Tutorial Features:
• Step by step examples showing data sets, product of two data sets and relations are shown in this tutorial.
• Examples displaying how to find the distance and midpoints between any two points are presented with the use of graphs.

Series Features:
• Concept map showing inter-connections of new concepts in this tutorial and those previously introduced.
• Definition slides introduce terms as they are needed.
• Visual representation of concepts
• Animated examples—worked out step by step
• A concise summary is given at the conclusion of the tutorial.

Coordinate Systems in two dimensions
        Definition of coordinate systems
        Definition of the four quadrants
Definition of distance and midpoint
Relations
        Definition of data sets
        Subsets 
        The product of two data sets
        The relation of two data sets
Line in a plane
        Definition of a line
        Definition of the slope of a line
        Parallel and perpendicular lines