积分符号

我会用费曼的秘诀积分符号内取微分。

I 'd use Feynman 's trick differentiate under the integral sign .

一般系统论四位创始人共同关心用系统概念来整合人类知识，并用∫（积分符号）作为一般系统研究会的标记。

The four founders of general system theory have a common concern , that is to integrate human knowledge through a concept " system " . And thus take ∫( integral symbol ) as the logo of the Society for General Systems Research .

根据定义，F通过平面曲线C上的通量是一个线积分，用符号F•n，ds表示。

Then the flux of F across a curve C is , by definition , a line integral but I will use notation F dot n ds .

为了提醒我们是在封闭曲线上做积分，经常在积分符号上加个圆圈，告诉我们，这条曲线自我封闭。

To remind ourselves that we are doing it along a closed curve , very often we put just a circle for the integral to tell us this is a curve that closes on itself .