TT MVANORFM. 253 



hincque dr-dxcoL(pUjC^n.(ptt d(^--^^'-^'^* 

 Qiiaeritur ergo, quomoJo hinc in formuiis (5-^) et 



Cdl^) ^^c^ difFercntialium dx et dj^ ad quie referun- 

 tur , rotio nouorum differentialium dr et (i(p introduci 

 dcbennr , et cuiusmodi hinc formulae loco earum fuit 

 proditurje. 



14.. Confideretur in genere fundio qiiaecunque 

 ipfirum x et j , qu;ie fit 1; , et quae eadem erit quo- 

 que funclio ipCirum r et (|). Cum igitur fit 



d-v=:dxfn)-^dy('4)^dr{'r?)-^d(t>(il) 

 crit pro dr et d^, fubltUutis valotibus per dx et dy 

 exprefli'5 , 



dx (S) -H dj (f|) - (/rcof Cl) + ^rnn.0) ( ^? ) 



_^ fd y cof,$ — d X jii. (p / "' V V 



\bi terminos tam per dx, quam per ^2'/, afFcdos feor- 

 fim aequ:iri oportet , ficque erit 



(aii — cof.q) (,>)-'—( j-^) et 



( J7 ) - fui.Cp( ^-) 4- — (^-| ). 



Sit breuit.uis gratia (^-7)=/) et (^)rr^, erit 



(li/)r=-/,fm.4)(j^)4-cofCP(j|)-^-^^^?) 



g/';i..:p , dj^ __ /m. :p d (7 . 



(^.^"j == p cor. <p('4) + fin. $ { jj, - isL* (^f ) 



^qcof:^ (dr. co[Ji dq 



rr ^ dy) "1" r ^aj ) 



Erit vero ex firmulis fupra propofitis: 



l^J_-~"; (^^)- -^-; (^-)zrcofCp; (~)-fin.Cj) 



1 i 3 "vnde 



