No products in the cart.

Under root 3 is irrational.prove that

CBSE, JEE, NEET, CUET

CBSE, JEE, NEET, CUET

Question Bank, Mock Tests, Exam Papers

NCERT Solutions, Sample Papers, Notes, Videos

Under root 3 is irrational.prove that
  • 1 answers

Gaurav Seth 6 years, 9 months ago

Let us assume that √3 is a rational number.

That is, we can find integers and (≠ 0) such that √3 = (a/b)

Suppose a and b have a common factor other than 1, then we can divide by the common factor, and assume that a and b are coprime.

√3b = a

⇒ 3b2=a(Squaring on both sides) → (1)

Therefore, a2 is divisible by 3

Hence ‘a’ is also divisible by 3.

So, we can write a = 3c for some integer c.

Equation (1) becomes,

3b2 =(3c)2

⇒ 3b2 = 9c2

∴ b2 = 3c2

This means that b2 is divisible by 3, and so b is also divisible by 3.

Therefore, a and b have at least 3 as a common factor.

But this contradicts the fact that a and b are coprime.

This contradiction has arisen because of our incorrect assumption that √3 is rational.
So, we conclude that √3 is irrational.

https://examin8.com Test

Related Questions

sin60° cos 30°+ cos60° sin 30°
  • 2 answers
X-y=5
  • 1 answers
Prove that root 8 is an irration number
  • 2 answers
Venu Gopal has twice
  • 0 answers
(A + B )²
  • 1 answers
Find the nature of quadratic equation x^2 +x -5 =0
  • 0 answers

myCBSEguide App

myCBSEguide

Trusted by 1 Crore+ Students

Test Generator

Test Generator

Create papers online. It's FREE.

CUET Mock Tests

CUET Mock Tests

75,000+ questions to practice only on myCBSEguide app

Download myCBSEguide App