Math, asked by Swamymani, 11 months ago

Root 3 minus root 5 is irrational number

Answers

Answered by Cynefin
2

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Answer:

#Here's ur answer...♥️

Step-by-step explanation:

3  - \sqrt{5 } \:  is \: an \: irrational \: no.

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Answered by Cosmique
7

 \large{\boxed{ \frak{ \red{question}}}}

Prove that √3 - √5 is an irrational number.

\large{ \boxed{ \frak{ \red{solution}}}}

Let, us prove it by the method of contradiction.

Let us assume that

√3 + √5 is a rational number then, it could be represented in the form p/q where q is not equal to zero, and p and q are co-prime integers.

so,

 \sqrt{3}  +   \sqrt{5}  =  \frac{p}{q} \\  \\  \sqrt{3}   =  \frac{p}{q}  -  \sqrt{5}  \\  \\ squaring \: both \: sides \: we \: will \: get \\  \\ 3 =  \frac{ {p}^{2} }{ {q}^{2} }   + 5 -  \frac{2 \sqrt{5}p }{q}  \\  \\  \frac{2 \sqrt{5} p}{q}  =  \frac{ {p}^{2} }{ {q}^{2} }  + 5 - 3 \\  \\  \frac{2 \sqrt{5}p }{q}  =  \frac{ {p}^{2} + 2 {q}^{2}  }{ {q}^{2} }  \\  \\ 2 \sqrt{5}  =  \frac{ {p}^{2} + 2 {q}^{2}  }{pq}  \\  \\  \sqrt{5}  =  \frac{ {p}^{2}  + 2 {q}^{2} }{2pq}  \\  \\

Here,

LHS is irrational because √5 is an irrational number.

but

RHS is irrational having integers

it means

LHS is not equal to RHS

this, result is due to our wrong assumption that

√3 + √5 is rational

hence, it causes contradiction

therefore,

√3 + √5 is irrational.

PROVED.

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