√6
let us suppose that √6 is rational number.
There exist two co-prime numbers , say p and q
So √6=pq
Squaring both sides , we get
6=p2q2..(1)
Which shows that ,p2 is divisible by 6
this implies , p is divisible by 6
Let p=6a for some integer a
Equation (1) implies = 6q2=36a2
⇒q2=6a2
q2 is also divisible by 6
⇒q is divisible by 6
6 is common factors of p and q
but this contradicts the fact that p and q have no common factor.
our assumption is wrong thus √6 is irrational