A ratio is a simple mathematical expression of the relationship of one item to another.
比率为一项目与另一项目之间关系的简单算术列式。
By very simple mathematical derivations, the practical expression of (Vzz), the expression of normal vertical gravity gradient, and the comment on the accuracy were given.
本文以极简单的数学推导，给出了正常重力垂直梯度的实用表达式，并对其精度作出了评价。
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