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怎么求x+1除以x-1的n阶导数.

题目详情
怎么求x+1除以x-1的n阶导数.
▼优质解答
答案和解析
  改写
   (x+1)/(x-1) = 1+2/(x-1),

   [(x+1)/(x-1)]' = [1+2/(x-1)]' = -2/(x-1)^2,
   [(x+1)/(x-1)" = [-2/(x-1)^2]' = (-2)*(-2)/(x-1)^3,
   [(x+1)/(x-1)]"' = [(-2)*(-2)/(x-1)^3]' = (-2)*(-2)(-3)/(x-1)^4 = 2[(-1)^3]*3!/(x-1)^4,
   ……
   [(x+1)/(x-1)]^(n) = 2[(-1)^n]*n!/(x-1)^(n+1).