Irreducible polynomial of prime degree

260 Views Asked by At

Consider the polynomial $$ f(x) = x^{p} + x^{p-1} + \ldots + x + 1 $$ over $\mathbb{Q}$, where $p$ is a prime number. Is it true that $f$ is irreducible?

1

There are 1 best solutions below

0
On

Yes, if $p=2$. No, otherwise: $-1$ is a root then.