Question

Question #60356

Answer 1

Let `NN` be the set of natural numbers (positive integers), then (a) `A={x in NN : x\mbox{ is a factor of 6}}={1,2,3,6}` and `B={x in NN : x<11 \mbox{ and } x \mbox{ is even}}={2,4,6,8,10}`. (b) `n(A)=4`, `A cup B={1,2,3,4,6,8,10}`, `A cap B={2,6}`

Explanation:

`n(A)` is the number of elements in `A`, `cup` stands for union (combine the sets), and `cap` stands for intersection (what do the sets have in common?). Sometimes people use a vertical line `|` rather than a colon `:` in the set-builder notation. The symbol `in` means "is an element of''.