English

If M = 1/3 - 2sqrt2 and N = 1/3 + 2sqrt2 Find N2 - Mathematics

Advertisements
Advertisements

Question

If m = `1/[ 3 - 2sqrt2 ] and n = 1/[ 3 + 2sqrt2 ],` find n2

Sum

Solution

n = `1/[ 3 + 2sqrt2 ]`

n = `1/[ 3 + 2sqrt2 ] xx [ 3 - 2sqrt2 ]/[ 3 - 2sqrt2 ]`

n = `[ 3 - 2sqrt2 ]/[ (3)^2 - (2sqrt2)^2 ]`

n = `[ 3 - 2sqrt2 ]/[ 9 - 8 ]`

n = 3 - 2√2

⇒ n2  = ( 3 - 2√2)2

= (3)2 - 2 x 3 x 2√2 + (2√2)2

= 9 - 12√2  + 8

= 17 - 12√2

shaalaa.com
Rationalisation of Surds
  Is there an error in this question or solution?
Chapter 1: Rational and Irrational Numbers - Exercise 1 (C) [Page 22]

APPEARS IN

Selina Concise Mathematics [English] Class 9 ICSE
Chapter 1 Rational and Irrational Numbers
Exercise 1 (C) | Q 7.2 | Page 22
Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×