不定和分
∑ x f ( x ) = ∫ 0 x f ( t ) d t − 1 2 f ( x ) + ∑ k = 1 ∞ B 2 k ( 2 k ) ! f ( 2 k − 1 ) ( x ) + C . {\displaystyle \sum _{x}f(x)=\int _{0}^{x}f(t)dt-{\frac {1}{2}}f(x)+\sum _{k=1}^{\infty }{\frac {B_{2k}}{(2k)!}}f^{(2k-1)}(x)+C.}