Let U ={1,2,3,4,5,6,7,8,9}
A = {1, 2, 3, 4}, B = {2, 4, 6, 8}, C = {3, 4, 5, 6}
Find (a) A' (b) B' (c)(A ∪ C)' (d) (A ∪ B)' (e) (A')' (f) (B-C)'
(a) A' = U - A = {1, 2, 3, 4, 5, 6, 7, 8, 9} - {1, 2, 3, 4} = {5, 6, 7, 8, 9}
(b) B' = U - B = {1, 2, 3, 4, 5, 6, 7, 8, 9} - {2, 4, 6, 8} = {1, 3, 5, 7, 9}
(c) =
Let U ={1,2,3,4,5,6,7,8,9}
A = {1, 2, 3, 4}, B = {2, 4, 6, 8}, C = {3, 4, 5, 6}
Find (a) A' (b) B' (c)(A ∪ C)' (d) (A ∪ B)' (e) (A')' (f) (B-C)'
Let U ={1,2,3,4,5,6,7,8,9}
A = {1, 2, 3, 4}, B = {2, 4, 6, 8}, C = {3, 4, 5, 6}
Find (a) A' (b) B' (c)(A ∪ C)' (d) (A ∪ B)' (e) (A')' (f) (B-C)'
∴
= {7, 8, 9}
(d)
= {5, 7, 9}
(e) (A')' = A (By involution law)
∴ (A')' = A = {1, 2, 3, 4}
(f) B - C = {2, 8}
∴ (B - C)' = U - (B - C) = {1, 2, 3, 4, 5, 6, 7, 8, 9} - {2, 8} = {1, 3, 4, 5, 6, 7, 9}
Id U = {1, 2, 3, 4, 5, 7, 8, 9}, A = {2, 4, 6, 8} , B ={2, 3, 5, 7} verify De Morgan's laws:
...(ii)
Hence, form (i)m and (ii), we have
(b)
If R is the set of real numbers and Q is the set of rational numbers, then what is R – Q?
R-Q = Set of irrational numbers =
If U = {a, c, d, e, f, g, h}, find the complements of the following sets :
(a) A = {a, b, c} (b) B = {d, e, f, g} (c) C = {a, c, e, g} (d) D = {f, g, h, a}
(a) A' = U - A = {a,b,c,d,e,f,g,h} - {a, b, c} = (d, e, f, g, h}
(b) B' = U - B = {a, b, c, d, e , f, g, h} - {d, e, f, g} = {a, b, c, h}
(c) C ' = U - C = {a, b, c, d, e, f, g} - (a, c, e, g) = {b, d, f, h}
(d) D' = U - D = {a, b, c,, d, e, f, g, h} - {f, g, h, a} = {b, c, d, e}
U = Set of alll triangles = {x : x is a triangle}
A = Set of all trinalges with at least one angle different
= {x : x is a triangle and x has at least one angle different
∴ A' = U - A
= {x : x is a triangle} - {x : x is a triangle and x at least one angle different }
= {x : x is a triangle and no angle is different }
= {x :x is a triangle and x has all angles equal }
= Set of equilateral triangles.
Hence, A' = Set of all equlateral triangles.