A DIFFERENZE FINITE E PARZIALI . 809 



(jy-X+l)...(f-2X+4) ()>-X+l)...(j>-2X+ 5 ) 



= „_. i....{x-z) " T „_, i„..(^-3) 



. _ (y-x+i) (7 -2x4-6 ) 



4-C -. -. 4-ecc. 



1 „_, 1 .... (x — 4) ' 



Ora è facile il vedere che 



(j>-ì)„..(jr-x+i ) __ (f-x+\)....(j>-ix + t ) 



i .... (x— 2) i....(x— 2) 



-+-(* — 3)" ; : ' 



1 ....(x — 3) 



(x — 2)(x — 4) (/ — x+i) (/— 2x4-6) 



-r • ; : 



2 1 .... (x — 4) 



. (* — 3K* — 4)(*— 5) (7 -jc 4-1) •-(7—2X4-7 ) 



2»3 i....(x— 5) -t-ecc. 



Similmente 



(;-i)..,.(;-x+2)^ (^ xt i)...(7-2X + ?) 



1 .... (x-s) i....(x— 3) 



+ ( ^- 3) ^- y +^ (■/--** + <?) 



1 ....(x — 4) 



(*-3)(* — 4) (/-jc+i)....(;-w + 7) 

 H • : 4- ecc - ; e 



2 I....(X — 5 ) 



cosi in feguito . Softkuendo tutti quefti valori avremo 



, Q-x + i)-.(;-2x + 4) (/-x + i)...(/-2^ + 5 ) 



yi ; : +(X—2)/l 



i....(x-z) „ i....( X -3) 



(x-s)(x — 4) . (y-x+i)....(j>-ix+6) 

 -j- - A ; ; l. ecc. 



+ B „ L...CX-3) + ( *" 3)B . .....(*- 4 ; * ecc> 



(;-s;+i)....(/-ax4ó) 

 + C — ; + ecc. 



I....(X 4) 



0>-x4-i)-lr-ax + 4 ) 0-x+i)... Q/-ix-ì-5) 



1 ... ( x — 2 ; „_, 1 ... ( x — 3) 



Tomo 21 Kkkkk 



