5± ^0 



a^ + a^-a^ + g<lo/2)H/_g gj^^ ^^^ ^ a^-a^)H - (a^ + a^-aj cos (a^ + a^-a^)H] 



r.- 



j±£o 



I -a -a + e<ro/2)H /_0 gjjj (.Q _Q _ a )H - (a - a^- a) cos (a^^a^-aju) 



r m n \ n r m n r m n r m n I 



a + a^ + a + e 



(ro/2)H( g-^ f^^ ^^^^ ^j^ _ (^^ ^ Q^ ^ Q J cos (a^ + a„ + aju) 



r ' m 11 T m 



r 2 



—5- + {a + a + a )' 



A r m n 



with 



(67) 



,+ ^n,±l^ 



2w fe. 



y-\gr^ ±c.>„ ±a.^)\\Ta,k^^ - aj^.k^ 



a ~a k -k 



2 /? 



R-=^ffy-K ±c.>^± a.„)][Ta„^^ aJJ^ 



'^^%±fP^](co^±.J 



m m 



fa„-aJ|l±^)(co„±..,) 



/e -k 



, m r 



'2/e 2 



Ca^ -a J + aL-^ - 1 



kj 2co„ 



k -k 



m 



T 



k -k 



2k 



^ (a^ + aJ+aU^^-l 



2 '^m ^ n' n 



(68) 



22 



