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Please solve and explain, I have a test ( i don't understand what it means by x|x is a digit

Please solve and explain, I have a test ( i don't understand what it means by x|x-example-1
User Jeneen
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1 Answer

25 votes
25 votes

Answer:

a. {3, 6}

b. {0, 1, 2, 3, 4, 5, 6, 8}

c. {0, 2, 5, 7, 9}

d. {1, 4, 8}

Explanation:

The sentence,

U = x ,

says "U is a set of all the x's such that, x is a digit" Which here, just says that U = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}. The vertical bar line symbol, |, means "such that". To the right of the bar is some description of the contents of the set. Instead, it could say U=x or it could say U = x is a positive whole number less than 10

So x is all the numbers in the rectangle. And then some of them are grouped together: F is {1, 3, 4, 6, 8} and G is {0, 2, 3, 5, 6} and 7 and 9 are in U but not in F or G.

The upside down U symbol in part a, means "intersect" So in "F intersect G", we put the numbers that are in BOTH F and G, that is 3 and 6.

In part b the U-looking symbol means "union" It is all the numbers in F and G all together. So "F union G" means ALL the number in either or both F and G: {0, 1, 2, 3, 4, 5, 6, 8}

F' means "Not F" and includes everything that is NOT in F. {0, 2, 5, 7, 9}

Since F is {1, 3, 4, 6, 8} and G' (not G) is {1, 4, 7, 8, 9} then the intersection (upside down U symbol meaning what is the same between the two sets) "F intersect Not G" is {1, 4, 8}

User Phillip Mills
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