Faisant (,^y = i, (,^) = i, (^) = o, (^)=ro, (i|) = ., on « 

 5^4/ - dx -i- dy -i- dq + dt-hdr -^ ds et \{/ z j -hy -i-q-i-t-h-r-hS. 

 L' integrale est donc 



z -h p -ht-}- ^s-i^Sr — F :(x-hy-hq -^-tH- s-hr^ 



§. 29. Soit encore N'=r (x — y^ (.X -{- z) s (r — O7 

 N^'' -(x —y) (x-i- z) -+- (r — j) , N ^^ r (x — j) (jr -+- %) r (s —0? 

 a~(i— r — s — t ~\- q -{- pq ~h sqy -\- spy) ts (z -h z) 



— (xz -h- rstq H- qxy H- 4- ^x + tx) (x — y) 5 

 P=i:(i — r— ^— ^-Hg-|-pgH-s(//H-ijDj)ri(xH-%) 



' — (xz-\^rstq-\^ qxy -{-sx-^^tx) (x y) 



— (i -Hr-j-j-H-^-hpH- gr/ H- /?j)^) ^^ (x -f- %) 



-H (r^s -h yz -h p -h q +• pr^t -^ p \y +- rx -h j:v) (x — /) ; 



Vzzi^i — r — j — t-hpq -h-q -h sqy -h ^pr) ^^ (x -H z) 



— (xz -h^r^^-HqfXj-f- ^x-h^x) (x -7) 



— (i -f- r -h s -h ^ "H jo -h qfr/ -h p^r) ^^ (^ + ^) 

 -h (rj^ -+-/-+ p -h q-h prst -h pxy -+- rx -h sx) (x — y) j 



5 iz: (rst -hyz-h prst -h p -h 9 -h pxy -h rx -h sx) (x — y) 



— (i -Hr-h^-h^-hp-h qry -h p^j) '"J (^ -h z) } 



^r (r^^-+-/z-»- prst-hp-hq-*-pxy -t-rx-hsx) (i-r-s-t-hpq-hq-hsqy-hpty) 



— (xz-hqrst-hqxy-hsx-htx) (i-hr-hs-ht-hp-i-qry-hpsy). 

 Je fais pour abreger : 



A — I — r — j — ^~h(/-t-j07-h q^y H- jo^/? 

 U zz: x% -h qrst -h qxy -h sx -h tx i 



