No products in the cart.

Root 5 irrational

CBSE, JEE, NEET, CUET

CBSE, JEE, NEET, CUET

Question Bank, Mock Tests, Exam Papers

NCERT Solutions, Sample Papers, Notes, Videos

Root 5 irrational
  • 1 answers

Sia ? 6 years, 5 months ago

Let {tex}\sqrt 5{/tex} is a rational number.
{tex}\sqrt { 5 } = \frac { a } { b }{/tex}(a, b are co-primes and b{tex}\neq{/tex}0)
or, {tex}a = b \sqrt { 5 }{/tex}
On squaring both the sides, we get
 a2=5b2  ---------------------------------(1)
Hence 5 is a factor of a2
so  5 is a factor of a
Let a = 5c, (c is some integer)
{tex}\therefore{/tex} a2 = 25c2 

From equation(1) putting the value of a2
or, 5b2 = 25c2

or b2=5c2

so 5 is a factor of b2
or  5 is a factor of b
Hence 5 is a common factor of a and b
But this contradicts the fact that a and b are co-primes.

This is because we assumed that {tex}\sqrt 5{/tex} is rational
{tex}\therefore{/tex} {tex}\sqrt 5{/tex} is irrational.

https://examin8.com Test

Related Questions

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