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Master Math: Pre-Calculus by Debra Anne Ross

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Chapter 3. Sets and Functions

Sets

• Any group or collection of objects can form a set. The objects in a set are called elements.

• For example, in the set of numbers:

  • S = {3, 5, 10, 17}

S depicts the set, and 3, 5, 10, and 17 are its elements.

• Because 5 is a member of the Set S, we write:

  • 5 ∊ S

The symbol for member is “∊”.

• Q is a set where, Q = {5, 10}.

Note that Q is also a subset of Set S.

• The symbol for subset is “⊂”, where Q ⊂ S.

• If P is an empty set, we write P = {}.

An empty set is also called a null set.

• An empty set is a subset of every other set, so the following is true:

  • P ⊂ Q and P ⊂ S

• An alternative method for describing a set is to write:

  • {x: }

This set contains values for x, which are described by what is written ...

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