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Mark the Correct Alternative in the Following Question: for Real Numbers X and Y, Define Xry If `X-y+Sqrt2` is an Irrational Number. Then the Relation R is

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Question

Mark the correct alternative in the following question:

For real numbers x and y, define xRy if `x-y+sqrt2` is an irrational number. Then the relation R is ___________ .

Options

  • reflexive

  • symmetric

  • transitive

  • none of these

MCQ
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Solution

We have,

R = {`(x, y) : x−y+sqrt2` is an irrational number; x, y ∈ R}

As, `x−x+sqrt2 = sqrt2`, which is an irrational number

⇒ (x, x) ∈ R

So, R is reflexive relation

Since, (`sqrt2`, 2) ∈ R

i.e. `sqrt2−2+sqrt2=2sqrt2−2`, which is an irrational number

but `2−sqrt2+sqrt2=2`, which is a rational number

⇒ (2, `sqrt2`) ∉ R

So, R is not symmetric relation

Also, (`sqrt2`, 2) ∈ R and (2, `2sqrt2`) ∈ R

i.e. `sqrt2−2+sqrt2=2sqrt2−2`, which is an irrational number and `2−2sqrt2+sqrt2=2−sqrt2`, which is also an irrational number

But `sqrt2−2sqrt2+sqrt2=0`, which is a rational number

⇒ `(sqrt2, 2sqrt2)` ∉ R

So, R is not transitive relation

Hence, R is Reflexive.

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Chapter 1: Relations - Exercise 1.4 [Page 33]

APPEARS IN

R.D. Sharma Mathematics Volume 1 and 2 [English] Class 12
Chapter 1 Relations
Exercise 1.4 | Q 34 | Page 33

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