first difference

• 一阶有限差,一阶差分

first difference的用法和样例：

例句

1. The phase velocity dispersion and the numerical phase velocity errors ofelastic wave staggered-grid high-order difference method in anisotropic medium havebeen studied.
   研究了各向异性介质中弹性波动方程交错网格高阶差分法求解的数值相速度色散和数值相速度误差。