Mapping Diagram.
http://wiki.answers.com/Q/What_is_a_diagram_that_s...

A "relation" is just a relationship between
http://www.chacha.com/question/howcanyoutellif...

If you x and y concepts in problem then try to form one equation such as in linear or quadratic or your choice and make sure of x and y concepts in algrebra as x and y co ordinate
http://www.fixya.com/support/t3099890show_mapping...

The points are plotted on the diagram attached. You test to see if this is a function by looking for two points that might lie on the same vertical line. There aren't any two points
http://answers.yahoo.com/question/index?qid=201311...
