1. ## Set Theory Problem

I need some help on subsets because this problem I have is giving me issues. If any of you could help me that would be wonderful.

Write all of the subsets of the following set: {1,2,5}

2. ## Re: Set Theory Problem

The empty set.
The three sets with one element in each.
The three sets with exactly two elements in it.
The full set.

3. ## Re: Set Theory Problem

So something like this?

A = {1}

B = {2}

C= {5}

D = {1, 2}

E = {2, 5}

Full Set = {1, 2, 3, 4, 5}

4. ## Re: Set Theory Problem

Originally Posted by marsandfruit
So something like this?

A = {1}

B = {2}

C= {5}

D = {1, 2}

E = {2, 5}

Full Set = {1, 2, 3, 4, 5}
Did you read Slip's response? You are missing $\varnothing$ and {1,5}, also the full set is {1,2,5}, not {1,2,3,4,5} ... 3 and 4 are not elements of the original set.

5. ## Re: Set Theory Problem

In general, if a set has n members, then it has $2^n$ subsets, including the empty set and the entire set. Here n= 3 so there are $2^3= 8$ subsets.