📐 Mathematics · Relations and Functions (Class 12) · JEE

For the binary operation a * b = a + b − ab on R, the identity element is:

Answer: 0.

Correct answer: B. 0

Explanation: a * e = a requires a + e − ae = a, so e(1 − a) = 0 for all a, giving e = 0.

Concept context

Types of relations, equivalence classes, one-one and onto functions, composition, and invertible functions