( 200 ) 



2 



2 n— 1 



•" + m + 



n — ] 



B -A 



C 



= 



and so 



" n—Y " V ( n — 1) c\ + 



AC-B* 



~~C~ 



da\ d'a . 



From [ — = ma — we derive : 



dxj dx* 



{2-m){B -\- Cxf 



or 



* + 



B 



-|/£ 



m(4C-C J ) 



C K 2—m C"- 

 By equating the two values of x thus obtained, we find the 

 equation : 



/>' 



1 



+ 



B 



C n—\ V |_(n— l) 2 C_ 

 from which follows : 

 AC— B* 



+ 



AC—B"- 



m AC—B" 



C s 



C s 



T 1 _ B~\ / m AC—B 1 

 + 2 L^l ~~~C]V 2^m~ C 2- 



2 — m C 3 



2 — m C' 



-»2 



or 



or 



1 — m 



2 — m 



l/^-Ëi-?Kï 



1 — 



^m(2 





AC—B 2 



in 



«„ — a, 



a,o— a, 



C 3 



a, — a. 



(n-1) 



«2 — «11 jA 



«is — «J / 



or 



1— w ^Ks— «i7) _ a ia~ a i 



\/m(2 — w) « 12 — «j 

 In particular it appears that m = 1 , if 



n — 1 



a„ — a. 



-i a 



a,„ — a. 



72; and if 



"is 



«IS - «X 



should be ^n, then m ^1, at least if a ls > ö r 



If m is known for certain value of x, the decrease or increase of 

 m may be derived from the equation: 



(2 — m) a = constant, 

 which constant is equal to zero, if a x a, = a 12 s , and has else the 

 sign of a x a % — a 1% -. 



