Numbers, Inequalities, Absolute Values Flashcards
Integer
…-3, -2, -1, 0, 1, 2, 3, 4, 5…
Rational Number
r = m/n where m and n are integers and n does NOT = 0
set notation
A set is a collection of objects, and these objects are called the elements of the set
write in set-builder notation as
A = { x | x is an integer and 0
Intervals
Certain sets of real numbers occur frequently in calculus and correspond geometrically to line segments.
Rules for Inequalities
- If a < b, then a + c < b + c
- If a < b and c < d, then a + c < b + c
- If a < b and c > 0, then ac < bc
- If a < b and c < 0, then ac > bc
- If 0 < a < b, then 1/a > 1/b
Absolute Value
The absolute value of a number a, denoted by |a|, s the distance from a to 0 on the real number line. Distances are always positive or 0,
|a| >/ 0 for every number a
Properties of Absolute Values
Suppose a and b are any real numbers and n is an integer. Then
- |ab| = |a||b|
- |a/b| = |a| / |b|
- |a^n| = |a|^n
The Triangle Inequality
If a and b are any real numbers, then
|a+b| /< |a| + |b|