📐 Mathematics · Relations and Functions · JEE

Let A have m elements and B have n elements (m < n). The number of injective functions from A to B is:

Answer: nPm.

Correct answer: C. nPm

Explanation: An injective function assigns distinct images. First element of A: n choices, second: n-1, ..., giving nPm = n!/(n-m)! injections.

Concept context

Ordered pairs, Cartesian products, types of relations and functions, domain and range. Foundation for calculus and Class 12 algebra.