§. 3. Si aeqiiatio I. multiplicetur psr cof. (J5 et II. 

 per fin.Cp, tumque ifta fiat combinatio: I. cof. C}) -f II. fin.j (p, 

 icolligitur inde: 



C^) cof.0 -T(J-f ) fin.(I) +(J^) fin Cp+V(||) cof.(p = 1 (|i') -Q; 



fimilique modo fi ifta fiat combinatio: I.fin.Cj)— Il.cof.cp, 

 habebimus : 



(^^) fin.(l5+T(^^) cof.(P-(f-J)cof.(I) +V(^^) fin.(I) =,^(^^)-P. 

 Prior aequatio integrata dat : 



T cof. 0) + V fin. (p =:/^ X (J (il|) - Q) ; 



et pofterior 



Tfin.(I) - V cof.(^rr/^i(4(^i^)-P); 



CX quibus aequationibus nunc facile colligitur:^ 



T z=: cof (pfd s (1 (^^>) - Q) + fin. (^/ds (i C^) - P) 



- (M) f^n^, m - Q) + (fcl/^ ^ (| (^^f) - P) ; 



ob cof. (J) =: (^^) et fin. <p — (1|). Similique ratione fit 



V=:ifin.(p/^/(|(4^)-Q)-cof.(p/^i(4(^^f)-P)', 



hinc 



V4s = ds{^)-ds.fw.<pfds(t{^)-q) 



- ds cof. (^fds ( J {^) - P) = ^ V^. ( J {^) - Q) 

 -^;./^i(|(^)-P); 

 at integrando: 



Vv ^fdxfds (| (^>) - Q) -fdyfds (J (^^«) - P) ; 



quae formulae omnino conueniunt cum illis ab llluftr. E«- 

 ]fro Tom. XIX. Nou. Commentar. propofitis: 

 Tii:- (^I/PV/ - {^-2^)f(^ds et G (J-f ) -fdyf?^ds -fdxfQ^ds; 



exiftente 



