Question

Write the relation R = {(x, x³ ) : x is a prime number less than 10} in roster form.
1. {(2, 8), (3, 27), (5, 125), (7, 343), (10, 1000)}
2. {(2, 8), (3, 27), (5, 125), (7, 343), (9, 729)}
3. {(1, 1), (2, 8), (3, 27), (5, 125), (7, 343)}
4. {(2, 8), (3, 27), (5, 125), (7, 343)}

Answer 1

Correct Answer - Option 4 : {(2, 8), (3, 27), (5, 125), (7, 343)}

Concept:

Domain of a Relation: Let R be a relation from set A to set B. Then, the set of all first components of the ordered pair belonging to relation R forms the domain of the relation R.

i.e Domain (R) = {a: (a, b) ∈ R}.

Calculation:

Given:  R = {(x, x3 ) : x is a prime number less than 10}

Prime number of 1 to 10 is {2, 3, 5, 7}

Relation of (x, x³); Where x is a prime number less than 10

⇒ {(2, 8), (3, 27), (5, 125), (7, 343)}