KnowledgeBoat Logo
|

Mathematics

Let r be a rational number and x be an irrational number. Use proof by contradiction to show that r + x is an irrational number.

Mathematics Proofs

1 Like

Answer

By seeking contradiction,

Let r + x is a rational number.

We know that,

Rational number can be expressed in the form of pq\dfrac{p}{q}, where p, q ∈ I and q ≠ 0.

So,

r+x=pqx=pqrx=prqq.\Rightarrow r + x = \dfrac{p}{q} \\[1em] \Rightarrow x = \dfrac{p}{q} - r \\[1em] \Rightarrow x = \dfrac{p - rq}{q}.

From above we see,

That x is a rational number.

This is not possible as in question it is given that x is an irrational number.

Our assumption of r + x being a rational number is wrong.

Hence, proved that r + x is an irrational number.

Answered By

3 Likes


Related Questions