mean value theorems of differentials的用法和樣例：
例句
- Rolle's theorem is a special case of the mean value theorem.
羅爾定理是中值定理的一種特殊形式。 - By defining the directed area of polygons, We went into its properties and applications andobtained several new fixed value theorems of polygons.
通過給出平面多邊形的有向面積，探討有向面積的一些性質和應用，提出一平面多邊形的若干新的定值定理。
