y'=(x-1)(x-2)...(x-2008)+x((x-1)(x-2)(x-3)...(x-8))'
=(x-1)(x-2)..(x-2008) +x (x-2) ...(x-8) +x*(x-1)*((x-2)...(x-8))'
=(x-1)(x-2)..(x-2008) +x(x-2)...(x-2008) +x(x-1) *(x-3)...(x-2008) +x(x-1)(x-2)*((x-3)...(x-8))'
=.
=(x-2008)[.]+ .+x(x-1)(x-2)(x-3) ...(x-2007)*(x-2008)'
将2008代入得
y'(2008) =2008*2007*2006*.*2*1