— 364 — 



Rappresenlata quesln osprossione (IS) con ■- ' •' ' ' ^'^ 



si avri'i ultoriornicnte v - ") 



(^^^ )=2:e3D;,(0.;-C0«.aJ -h2 I GD,«; 

 =— 48(3a'— 8ieja3 , 

 (-'^'f)= 2.,D/,(0a^— ;0..aj.,— GD;,(aJ — 2 4aja^ 



= 2J(27a)— lMa'a.-+-l28a')a3-}-^92:e.a',( , 

 e in conscgucnza 

 (39) A'_''=-ll2z^-h2;(3a^— 8ajs 



— (27a*-n.i«V,-hl28a;;-f- I022t,a3) . 

 Designato infine queslo valore colla formula 



avi'cmo 



c qtiindi 



(;0) A|^':r=25«> = 4* . •- -■■ 



