f(x)=In(1+x)在x=0处的Taylor展开式为

问题描述:

f(x)=In(1+x)在x=0处的Taylor展开式为

令 g(x) = ln(1+x),g(0) = 0;
[ln(1+x)] ' = 1 / (1+x),g'(0) = 1;
[ln(1+x)] '' = -1 / (1+x)^2,g''(0) = -1;
[ln(1+x)] ''' = 2 / (1+x)^3,g''(0) = 2!;
一般有:[ln(1+x)] ^(k) = (-1)^(k-1) * (k-1)!/ (1+x)^k,g^(k)(0) = (-1)^(k-1) * (k-1)!;
根据泰勒展开式有:
∴ ln(1+x) = x - x^2 / 2 + x^3 / 3 + ......+ (-1)^(n-1) * x^n / n + .