2-3 — 



ct sic porro , ideoque 



BrA, C=§ (B-6), D=f (C-c), E=f (D-cT), F=f (E-e), ete. 



Formata itaque serie 



T. S a 3.54 3». 5»^ , 3». 5'. 7. 38 . 



** 2 a * 2 a .4. a "t~ 2 a ./i a .6 a . ' 2 a 4 a .6^8 a ' C 



cujus ttrminos dicamus b, _/, b", _» //y , b ir , etc. ut sit 



B — b + _/-+- 6 X/ H- V" -± _> ,v ■+• 6' -f- cet. 

 praeterea computentur numeri 



. _ o tv j _, 2 .4 ,// — 2.4.6 y// j? — 2.4.6.8 , iv 



c — 5 , cfc _ 3 — o , e __ — — , / — g-^7j-- , etc 



sive posito 



§_=& f = y, «=->, §=:., f f = .r, etc. 

 supputentur numeri 



czzfib' , d — ^yb", e _= (3y 5 b'",f — |3y 5. b IV , etc. 

 Quibus praemissis erit 



A = B = & + _/+ _/ / + _/" + & IV + & v + cet. atque 



C = /3(B — &), D = y(C — c), E = <?(D— _Z), E=e(E— *% 

 G = £(F_/), etc. 

 ideoque tandem 



s = a sec. a(i — A) Arc. sin. -— • cot. a 



+ _j sec. a cot. a. >/ (1 — ~ cot. 2 a) [B + C . ** cot. 9 a 



. — cot. 4 a + E,- cot. 6 a -+- £ - 8 cot. 8 a ■+• cet.] 



§. 18. Cum sit (Fig. 6.) u_Pd, ideoque i> cot. *_D__, 

 semper ent — cot. a — Dy unitate minor ; unde cum etiam qm- 

 libet coefficiens C , D , etc. minor sit antecedente B , C , etc. 

 .eries B -+- C -_ cot. 2 a -+- cet. semper converget, etiamsi - cot. a 

 maximum induat valorem ^ __ 1. Praeterea hocce casu, vel 



37* 



