A r A r' zz \ a of y y' [cof ( £ - £ -+- 7r -7/) -+ cof(t> -4- $ - tt - ?r / ) ] J 



ArA2;zz-ay 2 fin2(£-7r), 



A r A i>"zz: - a y y' [fin (1? - 6 -+• tt- 7r 7 ) -4- &n (£ -+- £ -tt- tt') ] J 



A^Avzzfl^y^fm^- £-+-7r-7r / )-fin(t)-+- $~7r-7r / )] , 



Ar / A?/ / — -aV^fins^-T/-), 



A 1; A t?" =. 2 y y' [cof ("b - £ -+- 7r - i/) - cof (t> -+- $ - 7T - tt 7 ) ] : 

 unde angulo duntaxat 3&-1? retento , numerisque i conve* 

 nienter determinatis , reperitur 



-=mmoa»mm>.(^)-j(^> 



x y 2 cof (3 6 — £ — 2tt) 



vaa / 2 vaa 7 / 4 WaW J 



x yy 7 cof(3 £ — £ — tt — tt') 



~'«'-^«-«-««'(^') - ^> 



xy' 2 C0f(3$— £ — sV), 



ubi in priore termino eft i zz 1 , in fecundo i zz, 2 5 in ter- 



tio t zzs 3. 



$. 4 2 . Subftitutis iam aA <z) zz — ah {i) (J. 3.), valo- 

 ribnsque differentialium fupra ($. 5.) evolutis, reperitur 



aABz=[-^b (I) — |a 2 c (I) -+-«|e w ]y 2 cof(3$— 1> — 2tt) 



^[~3«b' 2 >-|-| a 2 c' 2) ~-f^]yy / cof(3^-t>--7r-7r / ) 



+ [Y^ 13, -I^c (3, + °^ ,3, JV /2 cof(3 S-D-stO. 



Abwx ^a ^caa\ /m/?. ScienU Tom, XI. O o o J. 43. 



