You take the y component, take the derivative with respect to x, take the x component, differentiate with respect to y, you should get the same answer. And that is important to know.
对y分量，关于x求导，对x分量，关于y求导，应该得到相同结果，这个知识点很重要。
2
A new method for determining directly trace component in interfering base by absorbance subtraction -second derivative spectrophotometry is proposed.
对利用差谱—二阶导数分光光度法直接测定强干扰基体中微量组分的原理和实验方法进行了探讨。
3
It has become a system in the entire financial market an indispensable component of the derivative transactions has become a measure of a mature financial market is mature signs.