Random questions that I need help with

[ioaus09]

Just wondering if anyone knows the answer of the question: How many elements does P(X) have, if |X| = 3?

also can anyone show me how to find it thanks

[/0]

Not sure if this belongs in spesh =P

Ok, so X has 3 elements. Let's call them:

.

is the set of all subsets of X.



(the null set is included since it is the subset of X with no elements!)

Have a go at showing that, in general, (try a counting argument)

[TrueTears]

Have a go at showing that, in general, (try a counting argument)

or try it algebraically, both ways are awesome

[i remember this was one of the first proofs i did when i started combinatorics xD]

[ioaus09]

ah oops wrong area lol, thanks anyway