(50) = 



8 ning. S <P =: t:ing. (11^-^^) — 

 H-tang. (33^^-HCl)}- 

 -^-tang. (56i°-H4); — 



H-t.uis. (7Sr-^0)- 



§. 40. Suniaimis nunc cti.im tt z 

 \idimus cllc 



-» 



tang. (iii 

 tang. (33 

 tmg. (56^ 

 tang. (7Sr 



^) 

 <P) 

 4)) 

 (p). 



/' -{- I , quo cnfu 



coC (2 / -f- 1) cp = a"- ' cof. cof. (^^^^- -t- CP) cof. (-'-^^ — 0) x 

 xcof.(-'? -^ 0) cof.(-ii- — Cl))cof.(-^ H-(1))X 

 y . . . . cof. ( ''t_ -i- CD) cof. (^- — Cb) , 



««-«-1 ■ '^ ^21-t-l '^'' ' 



hinc fumtis logarithmis crit 



/ cof. (2 /• -+- i) (J) z= / 2^ ' -^- / cof Cj) -+- / cof. (-*-?-j H- Cj)) 



-i-/cof (^;r^-c|)) .... ^ / cof.7->^ ^ cp) 



vndc diffcrcntiando nancifcimur 



(2 / -f- i) tang. (2 /■ -I- i) CP rz: tang. C|) -f- tang. (^-^ -+- Cj)) 



— t.'^"g- (iTil - ^) H- ^=^"g- (—17 -^ ^) 



— ^^^"S-Cnir-^) 



tang.C.;:^.-^Cp)-tang.(J^i^-C|)). 



§. 41. Cafum quo 2 ; -i- i — 3 iam cuoluimus , fit 

 igltur 2 /■ -f- I ~ 5 , crirquc 



5 lang. 5 C|) — tang. (p -f- tang. (36° -h C|)) — tang. (36° — Cj)) 

 -}- tang. (72° -f- <P) — tang. (72° — Cp). 



Sit 



