Indigitefur nunc fcmifTis diftantiae focorum per Ijt- 

 teram g, eritque vti ex Conicis conftat g — ^^r-:. Quum 

 igitur fjt 



c' — e 



fiet his valoribus adhibitrs 



•_^' ( «^'- O ( cof. (p- cof. (jy ) = (f cof. (|)- <r'cof. CpO' - (^'-0' 

 ct faifla euohitionc: 



'^'^^'-'^'f-^-"^- ^^-af/(i-cof.(|)cof.(iy) 

 -f'fin.c;)'-t''fjn.(p'''. 



Si nunc vt fupra flatuatur <^ -\-<^~t\ (^' — (p — 5 fict 

 tiili^^^^l-^nn.iefin.LS^afc-^f^-cofE-cof.a) 



— <;' ( I — cof e cof. 5 — fin. e fin. 5) 



— c'' ( I — cof. e cof. 5 H- fin. e fin. ^) , 

 Tndc colligitur 



(t'^-<:')fin-^^'n '^^(''-'^^'(^-«^«^•«cof J) 

 — 2 t' c' ( I — cof e) ( I — cof ^) 



Ad hanc autcm acquationem ctiam ope iihus, quae §. 20. 

 adhibita cft, facilc pcrucnictur; quum cnim fit 



h_ _ c<r'(c of (p-co£^ _ 2££^finJ_e_fin. : 5. 



f c^ — c c* — c 



tumquc fit /' =1 -11.. et g z^ 7^,, crit v — ^ ' hincquc 



^ — tf' 2 f f ' fin. •! e fin. ; 5 



~T /^ 



Inde autcm muhiplicando vtrinque pcr 4f f'. fin. Jcfin.;^, 



fict 



