-^ ) 100 ( ^■«. 



Dcmonftratio huius fummationis. 



Ponatur breuitatis gratia 2 fin. (P ~ ci et difcerpa- 

 tur feries iu has duas partes : 



. _y.cof. 2 4)-ia^cor.40+^a'cof.6$)-etc. 

 ^^^°'-^-'^-aMm.3:p->*fin. 5-P + U* fin.7^-etc. 



et vtriusque fummam fcorfim inueftigemus. Hunc ii> fi- 

 nem notctur, pofito 



cof Cp + V- I. fin. Cp=ip 



cof. Cp — y - I . fin. (p — q 

 finus ct cofinus angulorum muhiplorum fore 



cof <p - ^^ 

 cof. 2CprrS-i^^ 

 cof. 3 (p - iL^ 

 etc. 



fin. (p rz ,^ 

 fin. 2(p — -^- 



— <?- 



1 V — I 



fin. 3 ^ = ^-.--^' 



etc. 



quibus in nofira ferie fubftitutis prodit: 



.CP cofCp rz ^;^.^P'^;) _'ia^ (P^;) +;a^ ^£_;^;) - etc. 



Ponatur fumma feriei fuperioris ^ *, infcrioris vc- 

 10 — 1 — , ita vt habeamus: 



z(pCQi(p = l-h-~hr[^ eritque 

 _ S a /) p - ^^^ p* -^ • a' P* - ; a' P' + 



Pz= 



etc. 



laqq-la^q^-i-loL^q -'rc^'r -^ t;tc. 



_ C U' />' - » a* P' -+- ^ a' P' - ' «' P' -^ ^^^- 

 ^"' ^-ia'?' + ia*?'- ia^?' + ia'^' - etc. 



Ex 



