说明：  有一类模型，其回归参数不是线性的，也不能通过转换的方法将其变为线性的参数。这类模型称为非线性回归模型。在许多实际问题中,回归函数往往是较复杂的非线性函数。非线性函数的求解一般可分为将非线性变换成线性和不能变换成线性两大类。这里主要讨论可以变换为线性方程的非线性问题。
(There is a class model, the regression parameters is not linear, it can not be converted into a linear method parameters. Such model is called non-linear regression model. In many practical problems, the regression function is often more complex non-linear function. Solving the nonlinear function can generally be divided into linear and nonlinear transformation can not be converted into a linear two categories. Here we focus on nonlinear problems can be transformed into a linear equation.)