+图钭学技术大荸数学系 University of Science and Technology of china DEPARTMENT OF MATHEMATICS 向前差商 f(x0)≈ f(o+h-f(ro) h Xoth数 学 系 University of Science and Technology of China DEPARTMENT OF MATHEMATICS h f x h f x f x ( ) ( ) '( ) 0 0 0 + −  向前差商 x0 x0+h