हिंदी

(i) √3 is a rational number. (ii) The rationalising factor of √3 + 1 is √3 − 1. - Mathematics

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प्रश्न

(i) `sqrt3` is a rational number.

(ii) The rationalising factor of `sqrt3 + 1` is `sqrt3 - 1`.

विकल्प

  • Only (i)

  • Only (ii)

  • Both (i) and (ii)

  • Neither (i) nor (ii)

MCQ
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उत्तर

Only (ii)

Explanation:

(i) `sqrt(3)` is not a rational number; it is an irrational number.

This is because `sqrt(3)` cannot be expressed as a fraction of two integers. 

A proof by contradiction shows that if it were rational, it would imply a common factor contradicting the simplest form assumption.

Therefore, statement (i) is false.

(ii) The rationalising factor of `sqrt(3) + 1` is `sqrt(3) - 1`.

Multiplying by this conjugate removes the irrational part in the denominator or numerator since `(sqrt(3) + 1)(sqrt(3) - 1) = 3 - 1 = 2`, a rational number. 

Therefore, statement (ii) is true. 

Hence, only statement (ii) is valid.

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  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 1: Rational and Irrational Numbers - Exercise 1F [पृष्ठ ३५]

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नूतन Mathematics [English] Class 9 ICSE
अध्याय 1 Rational and Irrational Numbers
Exercise 1F | Q 1. | पृष्ठ ३५
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