48 



fiet 



S©, 



+ ëë)+Q-S(|^)+ss(|^), 



sive concinnius : 



ddz 9Q_, /Szy I 3S /92\ 



3^2 — d'y ^d~U "r" 9^ V3ll/ 



§. 9. Istos jam valores pro formulis differentialibus 

 secundi gradus inventes heic uni obtutui exponamus : 



1 /932\ 3P /92\ ) 9R fdz\ 



^' ydx^^) — ai \dt' "T" 9^ \Jû) 



+ pp(g)+ 2PrO + rr(|||), . 



jT / 992 \ 9P /9 2\ I 9R /92\ 



■^^' \dxdy) dy \Stl '^ dy V9Ù/ 



H- Pa(|5) + (PS + dR) (l^-J + RS (g), 



ITT /"— ^ — ?-^ /'^-'l -1- — (—\ 

 ^^^' \dyi/ -^ dy V9 f/ "T" d> V9ij/ 



-f-aa(S)+ 2.as(^) 4-ss(g)< 



quibus jungantur formulae dilïerentiales primi gradus : 



/3 Z\ T> /" *^\ I D /^ "^X 



O = i^ (9-;) + R O 



