Consider the relation R on the set defined by if and only if . Then, among the statements :
I. The number of elements in R is 17
II. R is an equivalence relation
Consider the relation R on the set defined by if and only if . Then, among the statements :
I. The number of elements in R is 17
II. R is an equivalence relation
Official answer: A
Count. Of the 25 pairs, only when a and b are non-zero with opposite signs: , or the reverse, 8 pairs. So R has 17 elements: I is true.
Equivalence? R is reflexive () and symmetric, but not transitive: while . II is false.
(A)