'>¥.^ 



) 7:^ ( 





quae regula ita commodius per diflfcrcntias cxponitur, fci- 

 licet rationc flgnorum lcpufita. Ex fcric numcrorum A , 

 B, C, D, E, ctc. formctur fcrics differcntiarum , dum 

 quilibct tcrminus iiiius fcrici a fequcntc lubtrahitur, 

 quac fit c, b, f, d, etc. Eadcm porio lcrc ex liac 

 fcric ditfcrcutiarum formetur lcries (ccundarum diffe- 

 rcntiarum, quac fit a' , b' , c', d', ctc. cx liac porro fcrics 

 tertiarum ditfcrentiarum , quac fit a\ b" , c" , d" , c', ctc. 

 atquc hoc modo vlterius doncc ad ditfercntias conlUntcs 

 pcruenidtur. Tum autcm ex terminis primis omnium ha- 

 rum fcricrum lumina fcrici propofitae ita dctcrmiuatur , 

 \t ea i\f 



; A - : fl + ; fl' - ;, a" + ,■ a'" - i a"" ^- ctc. 



§. aS. Hac rcgula ftabilita, cum fignis mutatis 



fit 



— j-— i-5 + i::-:;2 + 35-5i +7°- ctc. ct 



— ;zr2-7+i5-26 + 4.o— 57 + 77- ctc. 



hi tcrmini fcqucnti modo difponantur ac diffcrcntiac fub- 

 fcribantur: 



I, 5, 12, 22, 35, 51, 70 ctc. 

 4, 7, 10, 13, 16, 19 



3i 3i 3i 3» 3 



o, o, o, o 



2,7, 15, ^C, 40, 57,77eic. 



5, 8, II, 141 n, ^o 



3> 3> 3> 3> 3 

 o, o, o, o 



Hinc igitur colligitur forc 



-/r::-:-f-J — -;, fiuc s— ',, porro 



-/-:-:+-;=:;, fiuc /=:-; 



\ndc manifcflo conficitur cffc s-^-t — O. 



§. 29. 



