分段线性插值 0 X +1 X (x)=∑yl(x) =0 计算量与n无关 x,1≤x≤x n越大,误差越小, x-x X.≤x≤x 其它 n->oo n (x)=g(x),x0Sx≤xn10 分段线性插值              − −   − − = = + + + − − − =  0, 其它 , , ( ) ( ) ( ) 1 1 1 1 1 1 0 j j j j j j j j j j j n j n j j x x x x x x x x x x x x x x l x L x y l x 计算量与n无关; n越大，误差越小. n n n L x = g x x  x  x → 0 lim ( ) ( ), • • • • • • o x0 xj-1 xj xj+1 xn x y