What are tight bounds for $$\Phi_n(b)$$ where $\ \Phi_n()\ $ denotes the $\ n $-th cyclotomic polynomial , $\ n\ge 3\ $ and $\ b\ $ is a "large" positive integer ?
We can assume that the prime factorization of $\ n\ $ is known and hence $\ \varphi(n)\ $. $$b^{\varphi(n)}$$ is the obvious approximation and seems to be already quite good , in particular if $\ n\ $ is large as well. But this approximation can be too small or too big, I guess depending on $\ n\ $, but I could not find out yet how. Any reference or ideas?
From this document titled The cyclotomic polynomials - Notes by G.J.O. Jameson, we have from page $2$, section 1.2 (v), the following proposition:
I am not too sure, though, if these bounds are tight for large $b$, as I have just commenced my self-study of cyclotomic polynomials.