quadric equation meaning in English

二次方程

The linear regression models and the non - linear regression models are established respectively , which can be used in monitoring the grassland biomass based on the vegetation indices . finally , in order to establish the grassland biomass monitoring models with higher accuracy the different forms of the non - linear regression model were established respectively , including the quadric equation , the cubic equation , the logarithmic equation , and the exponential equation . the repeated tests indicated that the cubic equation is the best one in terms of the suitability of use in the study area
建立遥感植被指数和草地生物量的一元线性回归模型和非线性回归模型，通过反复分析论证得出，非线性回归模型相对于一元线性回归模型与实测生物量更为符合；通过分析植被指数与实测生物量的不同非线性回归模型的结果，表明三次方程y = - 18 . 626rvi ~ 3 + 220 . 317rvi ~ 2 - 648 . 271rvi + 691 . 093是最适用于监测研究区草地生物量的非线性模型。