(cof. l A cof. .; B + coC l C cof. ^ D) fin. i A fin. ; B fin. ^ a^ 



__ 5cof.i(A + B + C + D)cof.i(A4-B-C-n7 

 -~ ^cof ;(A + B+C-DJcof.^(A+B-C+DjS 

 t^' ^^ coq(A+-B+C+D)cf.^( A+B-C-D)cf.-:(A+-B+C-D)cf .nA+B-C-+D) 

 ^''^ " col.;(A-B+-C+-D)c(.:(B+CH-D-A)cl.:}A-B+C-D)cl.-:(A-B-C+D) 



§. 42. Deinde quum fimili ratione pofito arcu 

 DCz=f, demonftretur effc; 



(cof -; A cof ', B +- cof i C cof. : D) fin. ; C fin * D cof ^ c' 

 _ 5cof.-:(A+-B-C+-D)cof ;(A+-B+-C-D^? 

 — ^cof-:(A-B+C-D)cof:(A-B-C + D;S 

 (cof ;Acof tB4-cof;CcofiD)firi.-;Cfin.-;Dfin.;<;^ 

 _ 5cof-:(A + B+-C + D)cof.:(A+-B-C-D)^ 

 - ^of.:(A-B-fC + D)cof:(B+-C + D-A)S' 

 fin. : (fl -f- 1) i: fin. ; a cof ; c -+- cof ; a cof ; c — 

 ^C+-cofi(A4-B-^C-D)cof:(A4-B-C + D)5 

 ^ ^ +cof : ( A - B-i- C+- Dj 4- cof-: (B + C +- D - A)S " 



cof I (df -]- c) — cof. ^ a cof. \c — fin.la fin. 1 ^ z=: 

 ^ C+cof:(A-BH-C-D)cof.:(A-B-C + D)) 

 »' ^+cof:(A-i-B4-C-|-D)cof:(A-B4-C-D)S' 

 exiflenfc 



fcof-:(AH-B-i-C-f-D)cofi(A-^B-C-D)). 

 '^- ^co(. :(A-B-HC-D)cof-:(A-B-C + D)S' 

 ^i_yScof:(A-hB-+ C-I))cof :(A-^B-C-|-D)? 

 ^' ~ ?cor:(A-B-| CH-D)cof.:(B-hC-l-D-A;S' 

 >/ryfin.'Afin.'Bfin.:Cfin.:D(cof:Acof'B+cof:Ccuf;D). 

 Atqui ob 



a. cof. 



