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The number of all subsets of set {3.5} is___________ individual
Four! 3, 5, 3, 5 empty sets
The number of subsets of set {a, B, C} is?
Eight
This can be enumerated
An empty set is one,
There are three single element sets: {a}, {B}, {C}
There are three sets of two elements: {a, B}, {a, C}, {B, C}
It itself {a, B, C} is still one. A total of eight
Or think of it this way:
For each element a, B, C
There are two choices: put in a subset or not
So, 2 * 2 * 2 = 8
It's simpler
What is the number of subsets of set {a, B, C} D?
The number of subsets of set {a, B, C, D} is:
C4 (0) + C4 (1) + C4 (2) + C4 (3) + C4 (4) = 1 + 4 + 6 + 4 + 1 = 16
What is the number of subsets of set [a, b]?
Trouble
｛a｝
｛b｝
｛a,b｝
{} (empty set) {a, B}
4
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