说明：  matlab开发环境下，牛顿迭代法解非线性方程组，使用者把非线性方程组的M文件fx1(x)和非线性方程组导数的M文件dfx1(x)相应代入即可。
(matlab development environment, the Newton iteration solution of nonlinear equations, nonlinear equations to the user of the M documents fx1 (x) and non-linear equations of the M derivative document dfx1 (x) can be substituted into the corresponding .)