73 



Hactenus igitur noftrae formulae ad fequentes formas funt 

 reductae : t s 



J V sin 3% J . J 



/*Qj2v — —- f dv sn • 



3 

 Ysin 3& 



§. 28. Cum deniqtie fit y 3 =: ^^ — cos 3 3-, erit diffe- 



rentiando 3 w d v = - l^i-f* ideoqu eVz; =- ^^- c ™ 



..... r 3 sin 3 (£-<£) (sin .3 ($ - (fy)| , 



lgitur fit z; 3 = --JJ2. ent w =: r^ — -r- — — , unde 



& sm 3 $ sln 3 $|. 



fit ^y = — — — , ficque formulae noftrae, ad 



(siiii(J--Cp | sina$! 



folam variabilem Cj) reductae, erunt 



/Pdi? =— sin3^3 /-, .3—3 l^- — 3—- 



7 7 sin3$(sin 3 (^-Cp;)! 



y^eW — Sm3 ^ysin 3 (p(sin3(^-0))! 

 quarum formularum integratio haud exiguam dexteiitatem 

 in calculo angulorum poftulat. 



§. 29. TJt calculum ad folitas quantitates revocemus, 

 ftatuainus tang Cf) = t, tit fit 



sin (p = —J — ; et cosCl) = , unde fit 



yi-^tt >/n-tt 



a$ / cos$=r 7 _^:lj et d$sinCj)=-- — ^U 

 (i-*tt')l (1 -f-tt)l 



Praeterea vero habebitur tang 3$ = 3 _L=?, unde fit 

 sinsCfizr:-^ ^^ e t cos3([)= 7 'rrir* Hinc porro 



( I -+- tt i *~ ( I -K tt ;f ^ 



J\fri>4 Acta Acad. Imp. Scient. Tw. XIV. K. Confl- 



