Sets
3 marks · NormalWrite down the meaning of these three symbols as used in set notation: (a) (b) (c) (the prime symbol as in )
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(a) Subset or equal to; every element of the first set is also in the second set.
(b) Intersection; elements that are in both sets.
(c) Complement; all elements in the universal set that are not in the set.
Also accept: Descriptions in clear language; symbols' meaning explained.
Common mistakes: Using 'subset' instead of 'subset or equal'; mixing up intersection and union; confusing complement with inverse.
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Marking points
B1 · 1 mark · Correctly describes as 'subset or equal to' or equivalent.
B2 · 1 mark · Correctly describes as 'intersection' or equivalent.
B3 · 1 mark · Correctly describes the prime symbol as representing 'complement'.
Worked solution
a) means the set is a subset or equal to (every element is also in the other set).
b) means the intersection, or the elements common to both sets.
c) The prime symbol shows the complement: all elements not in the set.