MAT134Y5 Lecture Notes - Lecture 1: Square Root
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Real number: a real number is any number on the number line. It may be an integer, positive/negative, fraction, or decimal: square root 2 and pi cannot be written as fractions; these are called irrational numbers. S (intersection) t is the set of all elements of s are also in t (upside down u) S (union) t is the set of elements which belong to s, t, or both (u) A s means a is an element of s or. A s means a is not an element of s. Example: {12345} intersection {34567} = {3, 4, 5} {-3-2-1} union {-2-10} = {-3, -2, -1, 0} If a>0 then: absolute value of y = a then the number = y, absolute value of ya then y>a or y