III 



$. 27; Nunc iam fme pluribus ambagibus fimiles 

 formulas pro fequentibus terminis (3); (4); (5); etc. exhi- 

 bere poterimus. Ita pro termino (s) — C 9 fumto n numero 

 fatis magno , pofitoque ~~ — co, inveftigetur valor huius ex- 



preffionis: 



^ — |r:o-j-cof.3cor:(o-}-cof.<5wr: 2co-+-cof.9oar:30) , . . 



... -4-|cof.37rr:7r a 

 atque hinc confequemur hanc fummationem: 



1(3 ) -f= ( 2 n — 3) -+- (4 n — 3) -+ (<* re — 3)1 etc _ _2_ ^ 

 { +(2n + 3) + (4n + 3)4-(6n + 3)i ' n 

 Ita fi fuerit n — 12, ideoque co — 15°, habebimus: 



(3 ) -4- (21)-+- (45) -f- (^9) 



i 



-( 27 ) + (5i)-H( 7 5)S etC --' 2 - 



J. 28. Eodem modo pro termino fequente (4)z=D 

 in fubfidium vocetur ifta forma: 



S~| ~:o-j-cof.4cor:co-t-cof. 8coT: 2coH-cof. i2cor:3co .... 



. . . n-|cof. 47rr:7r , 

 unde fequens orietur fummatio 



SU)+( 2 rc-4)^(4?2-4) + (<^-4) + (8rc--4)? _ 2 < 



i -4-(2ft-4-4)-i-(4ft-i-4)-H(6n-f-4)-+-(8rc-4-4)S " n 



Hinc fi fumamus n~i2 et 10 — 15°, fummatio inde oriun» 

 da erit: 



£4) -f- ( 2 c) -4- (44) 4- (<*&) 4- (90 ? ' _ x £ 



-4- (28) -+ (5 2) -4- (76) -4- (ioc)S etC * —**" 

 Ex his iam fatis intelligitur, fi definire debeat in genere cha- 

 ra&er (X), computandam ante omnia effe formam: 



2) — |r:o-i-cof.\cor:co-4-coL2Xcor: 2co . . . . -4-Icof.X7rr:7r, 



tum 



? 



