No products in the cart.

Prove that √p+√q is irrational,where p …

CBSE, JEE, NEET, CUET

CBSE, JEE, NEET, CUET

Question Bank, Mock Tests, Exam Papers

NCERT Solutions, Sample Papers, Notes, Videos

Prove that √p+√q is irrational,where p and q are prime.
  • 1 answers

Sia ? 6 years, 4 months ago

Consider {tex}\sqrt { p } + \sqrt { q }{/tex} is rational and can be represented as {tex}\sqrt { p } + \sqrt { q }{/tex} = a

{tex}\Rightarrow ( \sqrt { p } ) = a - \sqrt { q }{/tex}

{tex}\Rightarrow ( \sqrt { p } ) ^ { 2 } = ( a - \sqrt { q } ) ^ { 2 }{/tex} (squaring both sides)
⇒ p = a2 + {tex}\left(\sqrt q\right)^2{/tex} - 2 a {tex}\sqrt { q }{/tex}

⇒ p = a2 + q - 2 a {tex}\sqrt { q }{/tex}

⇒ 2a {tex} \sqrt { q }{/tex}  = a2  + q - p

{tex}\Rightarrow \sqrt { q } = \frac { a ^ { 2 } + q - p } { 2 a }{/tex}

As q is prime so {tex}\sqrt { q }{/tex} is not rational but {tex}\frac { a ^ { 2 } + q - p } { 2 a }{/tex} is rational because a, p, q are non-zero integers which contradicts our consideration.

Hence, {tex}\sqrt { p } + \sqrt { q }{/tex} is irrational where p and q are primes.

https://examin8.com Test

Related Questions

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