04. Functions question bank (Maths)

Let \( X \) be a non-empty set and \( P(X) \) be the set of all subsets of \( X \).  
For \( A, B \in P(X) \), \( ARB \) if and only if \( A \cap B = \phi \).  
Then the relation is  

If \( R \) is an equivalence relation on a set \( A \),  
then \( R^{-1} \) is