CUET · MATHS · PYQ PAPER 2023
Let \(*\) be a binary operation on set \(Q\) of rational numbers given by \(a * b=a+b+a b\).
Then identity element is:
- A -1
- B \(0\)
- C \(\frac{1}{2}\)
- D 1
Answer & Solution
Correct Answer
(B) \(0\)
Step-by-step Solution
Detailed explanation
\(a * e = a\) \(a + e + ae = a\) \(e + ae = 0\) \(e(1 + a) = 0\) \(e = 0\) (since for \(a \in Q\), \(1+a \neq 0\) for most \(a\), thus \(e\) must be \(0\)) Identity element is \(0\).
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