Let F be a field and b != 0 an element of F. Define the mapping varphi:F[x]->F[x] by varphi(f(x)) = f(bx) for every f(x) in F[x]. Prove that varphi is an automorphism of F[x] such that varphi(a) = a for every a in F.

### Recently Asked Questions

- Tick out the drug belonging to non-narcotic antitussives: a) Libexine b) Tusuprex c) Codeine d) Aethylmorphine hydrochloride

- Indicate the expectorant with the reflex mechanism: a) Sodium benzoate b) Derivatives of Ipecacucnha and Thermopsis c) Trypsin d) Ambroxol

- Tick the antitussive agent with a peripheral effect: a) Codeine b) Tusuprex c) Libexine d) Glaucine hydrochloride