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设F(x)=x(x-1)(x-2)(x-3)····(x-100).求F(50)的导数

题目详情
设F(x)=x(x-1)(x-2)(x-3)····(x-100).求F(50)的导数
▼优质解答
答案和解析
设F(x)=x(x-1)(x-2)(x-3)····(x-100).
F'(x)=(x-1)(x-2)(x-3)····(x-100)+x(x-2)(x-3)····(x-100)+x(x-1)(x-3)····(x-100)
+x(x-1)(x-2)(x-3)····(x-49)(x-51)*……*(x-100)+x(x-1)(x-2)(x-3)····(x-99)
F'(50)=x(x-1)(x-2)(x-3)····(x-49)(x-51)*……*(x-100)
=50*49*……*3*2*1*(-1)*(-2)*……*(-50)
=(50!)^2