The thinking about the product of infinite infinitesimals .

关于无穷多个无穷小的乘积的一些思考。

Calculus has practical applications , such as understanding the true meaning of the infinitesimals .

微积分有著实际的应用，比如理解无穷小的真正含义。

Leibniz discussed with his english colleagues his interest in summing series and the geometry of infinitesimals , and he corresponded with them when he was back in france .

莱布尼兹和他的英国同事讨论他对级数求和和无穷小量几何学的兴趣，当他回到法国后仍与他们保持书信联系。