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A Binary Operation * is Defined on the Set R of All Real Numbers by the Rule a ∗ B = √ a 2 + B 2 for All A, B ∈ R . Write the Identity Element for * on R. - Mathematics

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प्रश्न

A binary operation * is defined on the set R of all real numbers by the rule \[a * b = \sqrt{  a^2 + b^2} \text{for all a, b } \in R .\]

Write the identity element for * on R.

योग

उत्तर

Let e be the identity element in R with respect to * such that

\[a * e = a = e * a, \forall a \in R\]
\[a * e = a \text{ and }e * a = a, \forall a \in R\]
\[Then, \]
\[\sqrt{a^2 + e^2} = a \text{ and }\sqrt{e^2 + a^2} = a, \forall a \in R\]
\[ \Rightarrow \sqrt{a^2 + e} = \text{a and}\sqrt{e + a^2} = a, \forall a \in R \left[ \because e^2 =e \right]\]
\[ \Rightarrow a^2 + e = a^2 \text{ and }e+ a^2 = a^2 , \forall a \in R\]
\[ \Rightarrow e = 0 \in R, \forall a \in R\]

Thus, 0 is the identity element in R with respect to *.

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अध्याय 3: Binary Operations - Exercise 3.6 [पृष्ठ ३६]

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आरडी शर्मा Mathematics [English] Class 12
अध्याय 3 Binary Operations
Exercise 3.6 | Q 15 | पृष्ठ ३६

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