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Question-166911




Question Number 166911 by rexford last updated on 02/Mar/22
Answered by MathsFan last updated on 02/Mar/22
suppose (√2) is rational  (√2)=(p/q) ⇒ 2=(p^2 /q^2 ) ⇒  2q^2 =p^2 .....(1)   2 divides p   2 divides p^2   let  r=(p/2) ⇒  p=2r.......(2)  2q^2 =4r^2   ⇒   q^2 =2r^2   2 divides q  2 divides q^2   p and p have 2 as common factor  but contradict the fact that p and q  are coprime  hence  (√2) is an irrational number.
suppose2isrational2=pq2=p2q22q2=p2..(1)2dividesp2dividesp2letr=p2p=2r.(2)2q2=4r2q2=2r22dividesq2dividesq2pandphave2ascommonfactorbutcontradictthefactthatpandqarecoprimehence2isanirrationalnumber.

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