Question

Prove that root 2 is not a rational Number

Answer 1

it is in the present 11th standard book on example and it is a language process to prove it

Answer 2

it is a indirest proof
we should write root 2 is rational
root2=a/b
root 2 b= a
take square on both sides
(root 2)2=(a)2
2bsquare = a square
2 divides a2
2 divides a also
a=2c

2bsquare=a square
2 b square=(2c)2 where a = 2c
2 b square=4 c square
b square= 2 c square
2 divides b
2 divies a and b

2 is common factor for a and b
but we know a and b are co prime
we went wrong
so root 2 is irrational