Let * be a binary operation on set Q of

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Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Applications of Derivatives

Question:

Let * be a binary operation on set Q of rational numbers given by $a*b=a+b +ab.$ The identity element is :

Options:

-1

$\frac{1}{2}$

Correct Answer:

Explanation:

The correct answer is Option (2) → 0

$a*b=a+b +ab$

for identity element $i$

$a*i=a=a+i+ai$

so $i+ai=0⇒i=0$ identity element