Problem 2E

What is the main characteristic that determines whether or not an element is a main-group element?

MATH 103 Chapter 2 Notes Set ollection f objects well defined ● {A} Element - ember of a et ● ∈ ● 1 ∈ A ● 5 ∉ A Sets are esignated by: ● Word description (1st 3 l etters of the alphabet) ● Listing r roster , , c } ● Set builder notation { x | x is the first 3 letters of the alphabet } Empty or ull et ● Ø r { } ● NEVER uses { Ø } Cardinal Number - number of elements in a set (how many) ● If A = { 1, 2, 3, 4 }, then n(A) = 4 (because there are four numbers, or elements, in that set) Finite