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Real Numbers

Question
CBSEENMA10006115

Prove that the following are irrational:

(i)  fraction numerator 1 over denominator square root of 2 end fraction

Solution

(i) fraction numerator 1 over denominator square root of 2 end fraction
Let us assume, to the contrary, that fraction numerator 1 over denominator square root of 2 end fraction is rational.
So, we can find coprime integers a and b (≠ 0) such that
rightwards double arrow space space space space space space fraction numerator 1 over denominator square root of 2 end fraction equals straight a over straight b rightwards double arrow square root of 2 equals straight b over straight a
Since, a and b are integers, straight a over straight b si rational, and so square root of 2 is irrational
So, we conclude that fraction numerator 1 over denominator square root of 2 end fraction is irrational.