Interval+notation

=__Interval Notation__=

What Is Interval Notation? Interval Notation is a set of numbers that are endpoints on a number line or the domain and range on a graph. They are put into parenthesis or brackets depending on if they are greater than, less then, greater than or equal to, and less than or equal to.

How Do You Know When To Use Parenthesis Or Bracket? When you use parenthesis the inequality is less than or greater then. Brackets are used when the Inequality is greater than or equal to and less than or equal to.

= < > [ ]= __<__ __>__

Union Sign (U)- A Union sign is used in Interval Notation when there are two inequalities to be graphed on one number line and between those to problems there is an __OR__. ex: x < -9 or x > -3 = ( - infinity, -9 ) U ( -3, infinity )

If the inequality is __NOT__ a or problem the answer is between or where the two numbers overlap. If there is no overlap the answer is no solution.

Examples: 1) -4 < x __<__ 9 = ( -4, 9 ]

2) -6 __<__ x < 1 = [ -6, 1 )

3) x < -9 or x __>__ 7 = ( - infinity, -9 ) U [ 7, infinity )

4) x __<__ 2 or x > 8 = ( - infinity, 2 ] U ( 8, infinity )

http://www.coolmath.com/algebra/cruncher/algebra-problems-interval-notation-1.htm - This website will give you some practice problems to work on to help study for the exam.