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√3 is not rational number |
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Answer» letLet US assume on the contrary that 3 is a rational NUMBER. Then, there EXIST positive integers a and b such that 3=ba where, a and b, are co-prime i.e. their HCF is 1 Now, 3=ba ⇒3=b2a2 ⇒3b2=A2 ⇒3 divides a2[∵3 divides 3b2] ⇒3 divides a...(i) ⇒a=3c for some integer c ⇒a2=9c2 ⇒3b2=9c2[∵a2=3b2] ⇒b2=3c2 ⇒3 divides b2[∵3 divides 3c2] ⇒3 divides b. From (i) and (ii), we observe that a and b have at least 3 as a common factor. But, this CONTRADICTS the fact that a and b are co-prime. This means that our assumption is not correct. Hence, 3 is an irrational number. |
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