— 667 — 



Se ora sì sostituiscono ad X... L... i loro valori [7] s [8] si otten- 

 gono le seguenti equazioni : 



R = — ^ \ SQndlg —) — cosd(;s -+- — ) 



Elnr 



S = „ sen^l — ^ — -^ -\ — ^-òì-i- cos^f — ^h i — %^) — , 



T = 



senOltJ — ) -+- cos^f — ^ ^n ^ , 



V mr mr) \ mr mTj | 





Elm' 



H= 



- sen^i — y-H^)-+- coséni ^-H — ) 

 ri \ mr/ \ mr/ 



K = =^ — sené^f^H- — ) -H coséni — t/ -^ -^] i — 



ri/(/-^ ^' * \ mr/ V ^ mr/ ) r 



Queste formole si semplificano alquanto ponendo : 



. . y 



tanga = , tang/5 = 



^ mr 



Z->r- 



y 



mr 



— 



z 



m^T» 



y 



mr 



— 



y ' 



m'r- 



poiché divengono 



^ 2Elm- [//-H^\ / 1 1 



\/— 2-2 H r^ sen(^ — a) , 



V m^r m r ^ ' ' 



[11] 



aS = \j 1 o-^ H ri • — cos(^ — /5) , 



r V m r m r r 



r V m r mr 



G = 0, 



^= — -T- V 1 -+- -2:^ sen(^ — a) , 



[12] { " r V m'? 



Elm-. 



^^ Elm\ I 1 oc .n . 



K = \/ 1 H ^ • — cos(6? -" a) 



r V m r r 



