古鲁金定理的推广

An extension of Paul Guldin's Theorem

在求旋转体体积的古鲁金定理的启发下，本文给出了沿一条曲线，用它的法平面去截一个立体，算出了截得图形的面积，再应用曲线积分来计算此立体的体积的方法．

In the enlightenment of paul Guldin's Theorem, a new way to calculate thevolume of a solid of rotation is given in this paper. The basic thought is as followsAlong a curve, we use its normal plane to intercept the solid, then we can getthe volume of the solid by mesns of curvilineal integral.