设函数f(x)=log以a为底x（a大于0 a不等于1）,若f(x1x2```x2005)=8,则f(x1的平方)+f(x2的平方)+···+f（x2005的平方）的值等于

f(x1x2```x2005)=8,loga(x1)+loga(x2)+loga(x3)+...+loga(x2005)=8log(x1^2)+log(x2^2)+log(x3^2)+...+log(x2005^2)==2[loga(x1)+loga(x2)+loga(x3)+...+loga(x2005)]=2×8=16