x^n+x^(n-1) ………… Factorization of X + 1 in complex number field and real number field

x^n+x^(n-1) ………… Factorization of X + 1 in complex number field and real number field

On the complex field: x ^ n + x ^ (n-1) x+1=(x-(cos(2π/(n+1))+isin(2π/(n+1)))(x-(cos(4π/(n+1))+isin(4π/(n+1)))…… (x-(cos(2nπ/(n+1))+isin(2nπ/(n+1)))
On the field of real number: when n is odd, x ^ n + x ^ (n-1) x+1=(x+1)(x²-2cos(2π/(n+1))+1)(x²-2cos(4π/(n+1))+1)…… (x²-2cos((n-1)π/(n+1))+1)
When n is even, x ^ n + x ^ (n-1) x+1=(x²-2cos(2π/(n+1))+1)(x²-2cos(4π/(n+1))+1)…… (x²-2cos(nπ/(n+1))+1)