由局部截断误差|T川=O(h), els7+(+h)T+…+(1+ML)7T (1+)xA=0(h)∑(1+1) (1+hL)-1 1+h-1 O(n2)=O(n) lim(1+hL)M h→>0 lim(1+hl =1im(1+hL)xN-x0=e(xx)与步长h无关常数 Eer方法以O(h)速率收敛:h→>0,e→0( ) ( ) ( ) 2 1 1 1 1 1 n N N n O N hL T h e T T T − hL = −  + + + + + 由局部截断误差 ，则 ( ) ( ) ( ) 1 1 2 0 0 1 1 N N N K k k k k hL hL T O h − − − = = = =   + + ( ) ( ) ( ) 1 2 1 1 1 N O O h hL hL h − =  = + − + ( ) ( ) ( ) ( ) ( ) 0 0 0 0 0 1 [ ] 0 lim lim 1 1 lim 1 N h h L h x x N N h L x x x x N h hL hL hL hL e → → − →  −  =    = = −    + + + 与步长 无关常数 ( ) → 0, e → 0. Euler 方法以O h 速率收敛：h N