“近似式”的英语可以翻译为：[计] approximate expression ...

这些公式使得这些点子上的导数近似式是非对称形式.These formulas make the approximations for the derivatives at these points in a nonsymmetrical manner.就准确度而言, 本研究所推导之近似式优于其他文献中所发表之相关公式.In terms of accuracy, the present approximation is superior ...