# Math Help - Clasic iredducible polynomial

1. ## Clasic iredducible polynomial

Prove that $f(x)=x^{p-1}+...+X+1$ is an irreducible polynomial over Z[X]

2. ## Re: Clasic iredducible polynomial

Hint: prove that $F(x)=f(x+1)$ is irreducible by using the formula for a truncated geometric series, and looking at the coefficients. Use the Eisenstein criterion.