(-1)^n-(1)^n=
\((-1)^n-(1)^n= (-1)^n - 1\)
Thanks Heureka,
I'll go one step further:
\((-1)^n-(1)^n= (-1)^n - 1 \)
If n is even then this is 1-1=0
if n is odd then this is -1-1=-2
