The identity element for the binary operation * defined on Q - \0\ as a * b = ab/2 is: - Mathematics MCQ Mathematics Mock Test - 3 2026 | ExamTest.live

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1 mark

The identity element for the binary operation * defined on Q - {0} as a * b = \frac{ab}{2} is:

Solution & Step-by-step Explanation

Let e be the identity element. By definition, a * e = a for all a . \frac{a \cdot e}{2} = a e = \frac{2 a}{a} = 2 Check: 2 * a = \frac{2 \cdot a}{2} = a .So, the identity element is 2 .

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The identity element for the binary operation * defined on Q - {0} as a * b = \frac{ab}{2} is:

0

1

2

None of these

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