§. 2. Statuannus autem breuitatis gratia 0Crjr-4-yr« 

 Yt fit .V ~ xr — y, tum vero fiat a — y — / et (3 — y — g, 

 vt prodeat O A —z -\-f et O B :=r s -h g. Quodfi iam vo- 

 centur anguli OCA=p et OCBn:^, ita vt fit p-^*^— C, 

 ex triangulo OCA, cuius latera funt OC—z; OA-z-i-f 

 et A C —■ a ^ colligitur : 



COf t> ZH ° ° -t-^ g — (z-H/l^ g a — i/s-4-// ^ 



Simili modo ex triangulo OCB, cuius latera funt OC—z; 

 OB —z-{-g et CB = ^, colligitur: 



r ^ bh-i-zz — {z-hg)^ b b — tg z — gg ^ 



' " '~~ ib z, <2.b z 



Qnoniam igitur angulorum p et q fumma datur zz: C , eui- 

 dens eft hinc incognitam z determinari poffe. 



§. 3. Cum igitur fit p -{- q — C ^ erit 



cof. C — cof. p cof. q — fin. p fin. q , 

 tum vero 



fm. C nr fin. p cof. q -f- cof. p fin. ^ , 

 cuius fbrmulae quadratum praebet : 



fm. C zzz fin.p'' cof q" -+- coC.p- fin. ^* -+■ 2 fin./) cof. <7 cof /) fin. q. 

 At vero ex priori formula efl; 



fm. p fin, q =:i cof. j!> cof. q — cof C , 

 quo valore fubftituto prodit 



fin.C* — fm.p' coCq- -\- cof /)* fin.(?* -\- zco(.p' cof.q* 



— 2 cof. p cof. q cof. C 5 

 hinc iam cum fit 



fin. p'' =: I — cof. /r et fln. q^ :zz x — cof </% 

 Iwec acquatio induet iftam formam : 



fin. C~ — cof p -4- cof. q — 2 cof p cof ^ cof. C. 



