IIT JEE , AIEEE Forum - Mathematics , Trignometry

sreejith

number of elements in P(P(P($)))) is

a)0 b)2 c)1 d)4

please find the solution of this problem?

$-null set

puneet

I guess the P suggested above is power set only.

Assuming this I am answering the question.

Now we now that P(A) where A is some set is 2^|A|where |A| is cardinality of set A.

So P($) = 2⁰ = 1

So P(P($)) = 2¹ = 2

And P(P(P($))) = 2²= 4.

Thus the answer is 4.

Cheers