Complement of a fuzzy set
The complement of a fuzzy set A is a new fuzzy set A Complement, containing all the elements which are in the universe of discourse but not in A, with the membership function
Complement of µA(x) = 1 - µA(x)
So, the complement of A will be
The first is (1,1). The first 1 is in U but not in A, so it should be added in the complement. The second 1 is because the membership function is 1- µA(x). 1-0=1.
The same reason why you get (2,1).
The third one (3,0.3) because it is (3,1-0.7)=(3,0.3).
Same reason why you have (4,1) and (7,1).
The member (5,0) is not included because , a singleton whose membership to a fuzzy set is 0, can be excluded .