等比数列{an}中,a8＝4,函数f(x)＝x(x－a1)•(x－a2)•…•(x－a8),则f′(0)＝
问题描述：
等比数列{an}中,a8＝4,函数f(x)＝x(x－a1)•(x－a2)•…•(x－a8),则f′(0)＝
答
f'(x)=f(x)/x+f(x)/(x-a1)+...+f(x)/(x-a8)当x=0时,f(x)/(x-a1),f(x)/(x-a2),...f(x)/(x-a8)都含x项,故都等于0所以f'(0)=(-a1)*(-a2)*...*(-a8)=a1*a2*...*a8=(a1*a8)^4=a1^4*a8^4=a1^4*4^4=256a1^4不知a1=?等不下去...