— i7 l — 



ita ut 



habeamus 







cot. 



A 



~~2 



r ' 





cot. 



B 



S . 



r > 





cot. 



C 



o ~ 



h . 



r 1 



- 



cot. 



D 



2 



i 

 ~r~'i 





cot. 



E 



2 



k 



r ' 



Cum igitur sit A-|-B-f-C-f-D-f-E~3cT, iieri oportet 



• A-f-B-f-C . D-f- E N 



cot. ( 1 —) zz: o, atque adeo 



. y A-f.B-f-C\ D-f-E 



cot. ( 2 ) * cot. —~ 1—0, 



Componendo autem colligitur 



A-f- 1? -f- C fgb — (a-hh)rr 



COt. 



r (fg -f- aft — rrj * 



D-f-E ik — rr ik — rr 



COt. -— __ 



2 r(i-\-k) dr 



unde sequens emergit aequatio : 



(a-hd-hh)r*—(adh-r- ik (a-h h) -f- fg (d + &)) f+fghikzz o 

 atque hinc elicitur'radius quaesitus 



r_/.» ± ,/^_ N 



existentibus nempe 



_ a dh -^ikCa -+.Ji)-\-fg( d -f- /*) 

 a-f- ci — | — /*. 



N = .fS hik 

 a + d-r-h 



33" 



