MathDB
function over set of polynoms

Source: Moldova TST 2005

March 21, 2005
functionalgebra proposedalgebra

Problem Statement

nn is a positive integer, KK the set of polynoms of real variables x1,x2,...,xn+1x_1,x_2,...,x_{n+1} and y1,y2,...,yn+1y_1,y_2,...,y_{n+1}, function f:KKf:K\rightarrow K satisfies f(p+q)=f(p)+f(q),  f(pq)=f(p)q+pf(q),  (\forall)p,q\in K. If f(x_i)=(n-1)x_i+y_i,  f(y_i)=2ny_i for all i=1,2,...,n+1i=1,2,...,n+1 and i=1n+1(txi+yi)=i=0n+1pitn+1i\prod_{i=1}^{n+1}(tx_i+y_i)=\sum_{i=0}^{n+1}p_it^{n+1-i} for any real tt, prove, that for all k=1,...,n+1k=1,...,n+1 f(pk1)=kpk+(n+1)(n+k2)pk1f(p_{k-1})=kp_k+(n+1)(n+k-2)p_{k-1}