Rationalising denominator of irrational number - Rationalising

We do not leave an irrational number in the denominator.

So, we rationalise the denominator.  Let us look at some examples

  1. Rationalise 1/√2
  2. Rationalise 1/2 +√3

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Some Identities (√𝑎)^2=𝑎 √(𝑎^2 )=𝑎 √𝑎𝑏=√𝑎 ×√𝑏 √(𝑎/𝑏)=√𝑎/√𝑏 (√𝑎−√𝑏)(√𝑎+√𝑏)=𝑎−𝑏 (𝑎−√𝑏)(𝑎+√𝑏)=𝑎^2−𝑏 (√𝑎+√𝑏)^2=𝑎+𝑏+2√𝑎𝑏 (√𝑎+√𝑏)(√𝑐+√𝑑)=√𝑎𝑐+√𝑎𝑑 + √𝑏𝑐 + √𝑏𝑑

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.