国际
经济合作
原理:利⽤指定点 周围的四个点构造 拉格朗⽇插值曲线: y t (y ,y ,y ,y )t −2t −1t +2t +2y (x )=y t −2(x −x )(x −x )(x −x )
t −2t −1t −2t +1t −2t +2(x −x )(x −x )(x −x )
t −1t +1t +2+y t −1(x −x )(x −x )(x −x )
国电物资商务网t −1t −2t −1t +1t −1t +2(x −x )(x −x )(x −x )
t −2t +1t +2+y t +1(x −x )(x −x )(x −x )
t +1t −2t +1t −1t +1t +2(x −x )(x −x )(x −x )
t −2t −1t +2+y t +2(x −x )(x −x )(x −x )
t +2t −2t +2t −1t +2t +1(x −x )(x −x )(x −x )
t −2t −1t +1
分母是可以直接写出来的,记 为⾃变量间隔:
h ≡x −t x t −1y (x )==y t −2
(−h )(−3h )(−4h )(x −x )(x −x )(x −x )
t −1t +1t +2+y t −1
轨道根数(h )(−2h )(−3h )(x −x )(x −x )(x −x )
t −2t +1t +2+y t +1
(3h )(2h )(−h )(x −x )(x −x )(x −x )
t −2t −1t +2+y t +2公安机关办理刑事案件程序
规定2013
(4h )(3h )(h )(x −x )(x −x )(x −x )
t −2t −1t +1[−y (x −x )(x −x )(x −x )
t −2t −1t +1t +2+2y (x −x )(x −x )(x −x )
关怀的人生t −1t −2t +1t +2−2y (x −x )(x −x )(x −x )t +1t −2t −1t +2+y (x −x )(x −x )(x −x )]t +2t −2t −1t +112h 3
1
接下来就是求该三次函数在 处的导数 所以
这就是计算⼀阶导数的四阶中⼼差分格式!x t y (x )
′t y (x )=′{−y [(x −x )(x −x )+(x −x )(x −x )+(x −x )(x −x )]
t −2t +1t +2t −1t +2t −1t +1+2y [(x −x )(x −x )+(x −x )(x −x )+(x −x )(x −x )]t −1t +1t +2t −2t +2t −2t +1−2y [(x −x )(x −x )+(x −x )(x −x )+(x −x )(x −x )]
t +1t −1t +2t −2t +2t −2t −1+y [(x −x )(x −x )+(x −x )(x −x )+(x −x )(x −x )]}t +2t −1t +1t −2t +1t −2t −112h 3
1
y (x )=′t =={−y [(x −x )(x −x )+(x −x )(x −x )+(x −x )(x −x )]
t −2t t +1t t +2t t −1t t +2t t −1t t +1+2y [(x −x )(x −x )+(x −x )(x −x )+(x −x )(x −x )]t −1t t +1t t +2t t −2t t +2t t −2t t +1−2y [(x −x )(x −x )+(x −x )(x −x )+(x −x )(x −x )]
t +1t t −1t t +2t t −2t t +2t t −2t t −1+y [(x −x )(x −x )+(x −x )(x −x )+(x −x )(x −x )]}t +2t t −1t t +1t t −2t t +1t t −2t t −112h 31
展璞计划
{−y [(−h )(−2h )+(h )(−2h )+(h )(−h )]
t −2+2y [(−h )(−2h )+(2h )(−2h )+(2h )(−h )]
t −1−2y [(h )(−2h )+(2h )(−2h )+(2h )(h )]
t +1+y [(h )(−h )+(2h )(−h )+(2h )(h )]}t +212h 3
1
(y −8y +8y −y )t −2t −1t +1t +212h
1