ideoque ob 



d y ■rzd IV cor. (^ — nvd^^ fin. Cj) et 

 d z :==: d IV i\n. (\:> -{- u; d (^ cof. (p ; 

 ^jf' + d z' z:^ d iv^ -+- w' d (J)* j 

 tumque ob 



dx^ — ^/-y^ cof. '^^—2.vdy\dv{in.7i cof. ;; 4- -y' </v)' fin. ?;' et 

 dw^ — dv^ fin. 7j" + ^v dydv fin. ;; cof v; + 1?' ^/yy' cof. V ; 

 fiet 



dT^- — df^ — ^vir+ir + x;» 



Cmilique modo : 



da:'-t-d y--f.d z» duM^jr' d S' -t- •Yu^_d^ <> ^ A i_ B , C \ 



dT- ■~dT^ V 1) ""^"i ^T-'* 



Quum igitur fupra inuenerimus: 



dT- — ^,» ^T~ j^, ; 



d d u — u ( d ^' -hd(P^f,n. 6- ) _ _B_ _U Ara/WM-v]) . 



dT- — a» "i~ ^^ j 



multipUcata priori harum aequationum per v , pnfteriori 

 per u, et addita ad priorem ^i!l+:El^i!jtl!ill^ ad pofterio- 



rem ^— ^-ji^ — —i confequemur lias acquationes diffe- 

 rentiales: 



vddv-i-iv^ _A , 'Bdu-hv cof.(yi + S) ) . j c . 



OT' — 'u ' Hi r~ — j 



nddu-Hdu' — ^ , A(iV-i- ucof.{f\^S] ) , c 



dT^ u *^ .u: r -^ • 



Quum vero in triangulo A C B, fit 



A B^ = A C^ -I- B C^ - 2 A C. B C. cof. A C B , 



introdu(flis expreflionibus Analyticis erit : 



a' z:: V' -\- tr -^ :i wu cof. ( 7] -f- ^ ) , hinc 

 cof.(;7-+-0)zr.-^-:-:, 



J^a Acad, Imp. Sc. Tom. VI. P. /. X ideo- 



