Define a relation R on the interval [0, 2 ) by x R y if and only if 2 x - 2 y = 1. Then R is :
- both reflexive and symmetric but not transitive
- both reflexive and transitive but not symmetric
- reflexive but neither symmetric nor transitive
- an equivalence relation
Answer
(4) an equivalence relation
Solution
2 x - 2 y = 1 1 + 2 x - 2 y = 1 2 x = 2 y
On [0, 2 ), x 0 and is one-one
x = y x = y
R = \(x, x) : x [0, 2)\, the identity relation.
Reflexive: x R x ✓; Symmetric: x = y y = x ✓; Transitive: x = y, y = z x = z ✓
R is an equivalence relation.
Answer: (4)