不好意思还要再问一下，1/(1+(wt+o(t))/(u
因为 1/ (1+(wt+o(t))/(u-1) ) -1 =( (wt+o(t))/(u-1) ) / (1+(wt+o(t))/(u-1) ), 而且除以t 有界. 你也可以用TAYLOR 展开, 假如学过: 1/(1+x) = 1 -x +x^2 - ... = 1-O(x).