:discrete math
fact: let s be a finite set with s=n.
then ps=2 n.
let s 1,2,3, 4,5, 6,7, 8,9}
a) how many subsets does s have in total?
b) how many proper subsets does s have?
c) how many subsets of s contain exactly 8 elements?
d) how many subsets of s contain the element 1?
e) how many subsets a of s satisfy the property that an1,2 ?
you