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求y=1/(x^2-3x+2)的n阶导数

2007-10-24 12:40:46却***
求y=1/(x^2-3x+2)的n阶导数:详解见图`````?

最佳回答

  • 详解见图`````
    2007-10-24 13:00:06
  • y=1/(x^2-3x+2)=1/(x-2)-1/(x-1)=(x-2)^(-1)-(x-1)^(-1) [1/(x-1)]'=[(x-1)^(-1)]'=-(x-1)^(-2) [1/(x-1)]''=[-(x-1)^(-2)]'=2(x-1)^(-3) [1/(x-1)]'''=[2(x-1)^(-3)]=-2*3(x-1)^(-4) …… [1/(x-1)]的n阶导数=(-1)^n*n!(x-1)^(-(n+1)=(-1)^n/(x-1)^(n+1) 同理1/(x-2)的n阶导数=(-1)^n*n!/(x-2)^(n+1) 所以y的n阶导数==(-1)^n*n![1/(x-2)^(n+1)-1/(x-1)^(n+1)]
    2007-10-24 12:50:53
  • 很赞哦! (42)