Consider the following relations in 1, then which of the following is ...
Relation containing less than or greater than sign is never equivalence relation. so option c is correct.
Reflexivity : |m|=|m| for all m ==> relation is reflexive
Symmetry : if |m|=|n| then |n|=|m| ==> relation is symmetric
Transitivity : if |m|=|n| and |n|=|p| then |p|=|m| ==> relation is transitive
hence |m|=|n| is an equivalence relation
Consider the following relations in 1, then which of the following is ...
To be an equivalence relation, a relation must satisfy three properties: reflexive, symmetric, and transitive.
a) m~n if and only if mn is divisible by 5.
To check if it is reflexive, we need to see if for any m, m~m. If we choose m = 5, then 5 * 5 = 25, which is divisible by 5. Therefore, it is reflexive.
To check if it is symmetric, we need to see if for any m and n, if m~n, then n~m. If m~n, it means mn is divisible by 5. But multiplication is commutative, so if mn is divisible by 5, then nm is also divisible by 5. Therefore, it is symmetric.
To check if it is transitive, we need to see if for any m, n, and p, if m~n and n~p, then m~p. If m~n, it means mn is divisible by 5, and if n~p, it means np is divisible by 5. Since multiplication is associative, the product of mn and np is (mn)(np) = m(np)(np). Since both mn and np are divisible by 5, their product m(np)(np) is also divisible by 5. Therefore, it is transitive.
Therefore, the relation m~n if and only if mn is divisible by 5 is an equivalence relation.