2楼: Originally posted by tianshui1001 at 2013-09-27 09:55:52
对刚才的帖子补充
\lim\limits_{\tau\to t }\frac{\cdot x'(t)}{|x(t)-x(\tau)|^2}
其中x(t)=(x_1(t),x_2(t)),\quad x'(t)=(x'_1(t),x'_2(t))
|x(t)-x(\tau)|=\sqrt{^2+^2}...