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Unformatted text preview: ality we are saying that both inequalities must be simultaneously true. In this
case 5 is definitely greater than -9 and at the same time is less than or equal to 6. Therefore, this
double inequality is a true inequality.
On the other hand, 10 £ 5 < 20 is not a true inequality. While it is true that 5 is less than 20 (so the second inequality is true) it is
not true that 5 is greater than or equal to 10 (so the first inequality is not true). If even one of the
inequalities in a double inequality is not true then the whole inequality is not true. This point is
more important than you might realize at this point. In a later section we will run across
situations where many students try to combine two inequalities into a double inequality that
simply can’t be combined, so be careful.
© 2007 Paul Dawkins 122 http://tutorial.math.lamar.edu/terms.aspx College Algebra The next topic that we need to discuss is the idea of interval notation. Interval notation is some
very nice shorthand for inequalities and will be used extensively in the next few sections of this
The best way to define interval notation is the following table. There are three columns to the
table. Each row contains an inequality, a g...
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This note was uploaded on 06/06/2012 for the course ICT 4 taught by Professor Mrvinh during the Spring '12 term at Hanoi University of Technology.
- Spring '12