1. Set X = {5, 7, 11, 13, 16,19}, Set Y = {1, 2, 5, 13, 19}?

1. Set X = {5, 7, 11, 13, 16,19}, Set Y = {1, 2, 5, 13, 19}





a. What is the union of Sets X and Y?





b. What is the intersection of Sets X and Y





c. Create your own set Z that is a subset of Set X.

1. Set X = {5, 7, 11, 13, 16,19}, Set Y = {1, 2, 5, 13, 19}?
a. Union means everything in X or Y, so XUY={1,2,5,7,11,13,16,19}. Do not repeat elements.


b. Intersection means everything in both X and Y, so X(intersection)Y={5,13,19}.


c. Subset just means that it is contained in X, so an example would be Z={7,11,16}. There are actually 2^6=64 possible choices.
Reply:A more interesting or perhaps trivial example in c) is:





Z = empty/null set





The null set is a subset of every set. Try to prove it yourself if you are not convinced.
Reply:X U Y= {1,2,5,5,7,11,13,13,16,19,19}


X INT Y = {5,13,19}


Z={5,11}, Z ={x1,x2,...,xn}
Reply:X ∪ Y is the set of all elements that belong to either set, so


X ∪ Y = {1, 2, 5, 7, 11, 13, 16, 19}





X ∩ Y is the set of elements that belong to both sets, so


X ∩ Y = {5, 13, 19}





Since X has 6 elements, it has 2^2 = 64 subsets. I like Z = ∅


(∅ is a subset of EVERY set)


Z = {5, 7, 11, 13, 16,19} is nice too!
Reply:a. {1, 2, 5, 5, 7, 11, 13, 13, 17, 19, 19}





b. {5, 13, 19}





c. {11, 13, 16}