I need help on proving such that no integer k exists.
I assume the to proof this I need to use contradiction, assume there is some k such that . But Im having trouble finding a contradiction.
As you say, we will try to find a contradiction. First note that
The fact that implies since
Now implies thus and then ( In general we have that if and only if )
We then write that is which is not possible since and so (expand using the binomial theorem)