Question

Prove that `sqrt(5)` is irrational.

Answer 1

`sqrt5=a/b` (wnere a and b are Co-prime Numbers)
`a=sqrt5b`
squaring both side
`a^2=5b^2`
`a^2` is divisible by 5
a is also divisible by 5
similarly, b is divisible by 5
which means 5 is common factor of a and b
so, a/b is irrerational which makes `sqrt5` irrerational