Class 11

Math

Co-ordinate Geometry

Straight Lines

Let $S={1,2,3,4}$. The total number of unordered pairs of disjoint subsets of $S$ is equal to

- 25
- 34
- 42
- 41

Each element can be put in $3$ ways either in subsets or we don't put in any subset.

Total number of unordered pairs of disjoint subsets,

$=23_{n}+1 =23_{4}+1 =41$