MATH 115 QUESTIONS CORRECTLY ANSWERED

Union Rule for Sets - If A and B are sets


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n(A∪B) = n(A)+n(B)-n(A∩B)




What does ⊂ mean?

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proper subset




If U is a universal set and A is a subset of U, then the set of all elements of U
that are not in A is called the what?


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complement




What is... A∩(B∪C) = (A∩B)∪(A∩C)?


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Distributive law for intersection




Is repetition of elements allowed in roster notation and in set builder notation?


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Yes, {1, 1, 2, 2, 3} = {1, 2, 3}

{x|x is a letter of the word later} = {x|x is a letter of the word latter} =
{x|x is a letter of the word relate}

, A restaurant has 5 different entrees and 6 different side dishes. How many
ways are there to select a meal consisting of an entree and a side dish?
(a) 11
(b) 5
(c) 30
(d) 5/6
(e) none of the above


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(c) 30




What if now, Mr. Potato Head has 3 hats, 5 mustaches, and 4 kinds of glasses,
how many ways are there to dress him up?


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We can iteratively apply the multiplication principle to find that there
are
3 ∗ 5 ∗ 4 = 60 ways to do this.




Example of a set-builder notation.


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B = {x|x is a letter of the English alphabet} This is read as "B is the set
of elements x such that x is a letter of the English alphabet."