- #1
Supierreious
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Homework Statement
The Question data is as follows :
Consider the following sets, where U represents a universal set :
U = {1, 2, 3, 4, ∅, {1}}
A = {1, 3}
B = {{1}, 1}
C = {2 , 4}
D = { ∅ , 1, 2 )
Homework Equations
Which one of the following statements is true ?
1. The cardinality of U, ie |U| = |A| + |B| + |C| + |D|
2. {} ⊆ U
3. {∅, {1}} ∈ U
4. U union B = B
The Attempt at a Solution
1. So on this one I attempted, it is clear that this is not the case, and this statement is false, due to the fact that the cardinality indicates the amount of elements included in the set. The set for U , and the other sets' cardinality differ. If you would like me to illustrate what I have found, let me know , I don't mind adding it here.
2. This to my knowledge is true. If {} is an empty set, it does not have any element that is not in U, and is thus possible to 'reside' as a subset, in U. To my knowledge this is then true.
3. To my knowledge, this one is also true. The problem I have with this question , is that only one can be true, so either 2 or 3 is true. A set can be an element of another set, like in this case ( I read up on a couple of other articles on this website - if I am wrong with this one, please point it out to me, so that I can assess my understanding of this subject).
4. The union of U and B, will be the composition of all the elements in U, as well as the elements in B, without any duplication of elements. In a Venn diagram this will thus be the 2 circles, together, with the whole field ( of both circles) coloured in. So the sets together will be more than just the set B, and thus be incorrect.
There is no further information required.
Background from me : I was a LAW student, and changed to BSc Computer Science, and I am studying through Unisa in South Africa. This is part of one of my assignments for a subject COS1501, and the assignment is due next month, so I am not trying to catch up time by submitting my inquiry to you to answer, this is well in advance and my understanding is lacking , which I require assistance with.
Your advise, even if you point me in the right direction, will be highly appreciated.