Facta enim divisione per côs. i 4> et multipUcando per 

 ^1 — ncos.Cp)^"^* habebimus : 



X(X-Hi) n*—X(X 4-1) n* cos.Cj)* —a— 2 a »cos.4)H- an* cos.Cp* 



■4- 1 COS. <P —tn cos.Cp* 



unde statim concluditur fore : 



ai= X(XH- 1) nn, 



è Z3: 2 a n :=: 2 X (X -r 1) n', 



C =z bn — an^ — X (X -f- i) n^ — X (X -\~ 1) ?i* (n* — l) ; 



quibus siibslitutis in termino illo ultimo, binisque priorîbus . 

 terminis additis, fiet : 



\ ' ( I -^ îl COS. (pj^ 



9 A J X n [1 — I (X -I- 1) n^] eoÂ (^ tos. i $ 



X(X-)-On^(.i. — 71-2; c o'i. <p^ COS. 1 (t> 

 (7— TcôsT^)'^ -+- ^ 



;- 



lP*acta nunc comparatione nànciscimur valores 



/ =: i i -f- X (X 4- 1) n* , 



g =: — X n (1 — 2 (X H- 1) n^), 



quibus inventis aequatio differentio - differentialis quae* 

 sita erit : 



fu-HX(XH-i)n']z--M[i-2(X-M)M^]|5-n»(i-^n^)|^: = o 



in cujus membre 2 duplicis generis termîni occùrrunt, 



Mfmoirts 4itAead, T,r. ^^ 



