DANS LES POLYÈDRES. 435 



P'sin((p— a-")— P"sin(<p— *.') =: P'sin[(p--rt,— («."--et)] 



— P"sin[(?— ct-H(ec— a,') 

 = sin(?WflL) { P'eos(c(,"— c(,)-P"cos(a,-a-') \ 



[12] ^ ~cos(^ût.)|P'sin(<t"^ct)-4-P"sin(d,-x')| 



= jP'cos(<t"— rt,)— P"cos(ct— £t')jsin(— (pa,) 



-HPsin(c(,'— ct,")cos(<p— cl) 



[P'cos(a"— a)— P"cos(<t— a') "I 

 sin(<ï'— a") J 



[13] M = SjF(pcos6|Qsin(<p— a.)-f-Pcos(<p— 0.)} 



-+:/?sinô i Qsin((?— ct,)-i-Pcos(<p— cl) | j . 



T 



[14] :r:SjF(pcos[e/cos((p-ct,)]-+-/?sin[9/cos((p-ct)]|cos[ÔQsin((p-cL)] 

 -*- 1 /?cos[e/cos((p-c(,)]-F<psin[Ô/cos(<p-ct,)]lsin[ÔQsin((p-a,)]. 



[15] =|(F<p-*-F(7r4-2at.— (p))cos[ô/cos(?— et.)] 



^C/?-/('^2a^(p))sin[6/cos((f5— ct)]|cos[ÔQsin((p-cL)] 

 -H I (— F(p-HF(7r-H 2 £t— ^))cos[ô/cos(<p— cl)] 

 Afi'-^Â'^^ 2 ct-(p))sin [e/cos(?-cL)] { sin(ÔQsin((p-cL)] . 



[F(p-HF(7r-i- 2 CL— ?)] cos[/ôcos((p— et,)] 



rig-i ) -^[/?>— /('7r-H2cL— <p)]sin[/ôcos(9— cl)] = 



[— F(p-HF('7r-+- 2 CL— ip)]sin [/ôcos(ip— et)] 



-*-[./^■+/('^-^-2£^-?)]ços[/âcos((p — «.)] zr 



:[F?-4-F(2cL-ç.)]cos[/6cos(?-a.)] 



fj^l ) -t-[/^-t/(2<t— 'P)]sin[/9cos(?— cl) = 



< [-F9-+-F(2c^-?)]sin[/9cos(?-ct,)] 



-*-[/?-/(2ot— 9)]cos[/Ôcos(?-cl)] p= . 



55' 



