推论 (1)C∑f(x=∑fx) (2)[Cf(x=C(x); (3)ⅢIf(x)=f(x)/2(x)…fn(x) l: +…+f1(x)f2(x)…fm(x) =∑Ⅱf(x)/k(x) i=1k=1 k≠i推论 (1) [ ( )] ( ); 1 1   = =  =  n i i n i f i x f x (2) [Cf (x)] = Cf (x); ( ) ( ); ( ) ( ) ( ) (3) [ ( )] ( ) ( ) ( ) 1 1 1 2 1 2 1 =    + +     = =  = = n i n k i k i k n n n i i f x f x f x f x f x f x f x f x f x   