Set Notation A n (B u C)

A

andremac1996

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Jan 9, 2015
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Just a bit stuck here

Set A = x,y,x
Set B = x,y
Set C = x

So is A n (B u C) the NULL set as in its empty ?

Thanks
 
andremac1996 said:
Just a bit stuck here

Set A = x,y,x
Set B = x,y
Set C = x

So is A n (B u C) the NULL set as in its empty ?

Thanks
Click to expand...
Go back to the definitions.
What does A ∪ B mean: It is the set of those elements which are either in A, or in B, or in both A and B.

What does A ∩ B mean: It is the set that contains all those elements that are in both A and B.

Take it one step at a time. First do (B u C). The do A n (B u C).
 
andremac1996 said:
Just a bit stuck here

Set A = x,y,x
Set B = x,y
Set C = x
Click to expand...
What does your book mean when it says that sets (such as "Set A") are "equal" to lists of elements (such as "x, y, x")? Why, in the case of Set A, is "x" repeated? The usual set notation would say something more like "Set A = {x, y, z}" or "Set A = {x, y}", rather than what you've posted, is why I ask.

andremac1996 said:
So is A n (B u C) the NULL set as in its empty ?
Click to expand...
What are the elements of B-union-C? (Please write out what you get for this.) What are the elements, if any, of the intersection of A with the result you just go? (Please write out your results for this, too.) Is this "nothing", or something else? ;)
 
So here is my interpretation (I'm not the original poster but I'm trying to learn this material in school)

B u C= {x,y}

A= {x,y,z}

Therefore

A n (B u C)
= A n {x,y}
= {x,y} n {x,y}
= {x,y}
 
vashts85 said:
So here is my interpretation (I'm not the original poster but I'm trying to learn this material in school)

B u C= {x,y}

A= {x,y,z}

Therefore

A n (B u C)
= A n {x,y}
= {x,y} n {x,y} You have the wrong set for A here since A= {x,y,z} and not {x,y,}
= {x,y}
Click to expand...
You luckily arrived at the correct answer since you wrote the wrong set for A. Of course it could have been a typo on your part.
 
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