Then we discuss the necessary conditions for the limit curve to be C0,C1,C2 respectively and give the derivative and second derivative of the limit curve at vertex and midpoint. 隨後我們討論了極限曲線連續，一階連續，二階連續的必要條件，並給出了極限曲線在頂點以及中點處的一階導數與二階導數顯式公式。
The first order derivative spectrophotometry was used for determination of ofloxacin in its gel.The interference of other ingredients can be eliminated. 採用一階導數分光光度法直接測定氧氟沙星凝膠劑的含量，能消除其它組分的干擾。
