= (I70 = 



vnde fimul colligitiir forc 



S. J (w — O = S. i iv — <•/) ct u — i/ znv — v'. 

 Dcniquc vcro prodibic 



e C.\ (u-^i/) S.l(u-t/) zn e'C.l (v-i-v') S.l (v-v^, 

 hoc eft e(S.u-S.u')z=ze' (S.v-S.v'), fiue 



t^ K V'^ *>/ ^ ,^ccoj.(p .-f-ecq/.cP'^' 



g^ y( p'- — i) ( -'"'■ 'i' ''"■ ^' ) 



ct , ob u — // := v — v' , 



Arc. cof. (l^ti^) — Arc. cof. (ldzi^;)=r: 



Arc. cof. (1-^14^^-) — Arc.cof.( " ^"^;^J . 



§. 2 1. Circa dcinoiiflrationcm noflram in fupcrioribus 

 nllatnm notari nicrctur , cam aiiqu-.into faciliorcm euadcrc (i 

 ponatur angulus (^''rro, quo in cafu radius vecflor r^ in ip- 

 fum axem Ellipfis incidct, critque K — _^ — , ipfi autem dc- 



monllratio tunc hunc in rnodum concinnabicur. Ob r -t- r' - ^ -^- ^" 

 ct j zn c- fict 



(r-|-r7-4.rKcoflcr/zz(^. + ^0' — 4f^W.I(vj.-vi/V, 



ex quo colligitur: 



cof.^cDyri-^-f) __ . _^.^_ cof • rviy-vi.") 



Vl^i -t-^ cof.Cp; V(i-H-f'cofvj/;(n-f'cof.\|/0* 



Tumquc cx acquationc r -|- r' — a _|- ^^" , ifthaec deducitur; 

 fcof;(|)'r 1-4-0 _ fYcof'v^'cof:vl/^' ^i-^f0'-fi n.'vJy-fin.'v|/"Yi-O' 



i-hfcof^I) ~ {i-he' cof vpj (I -I- f cof \p') 



Hcic autcm fi ftatuatur 



Y 2 « = 



