where 



At d N,M 



N " (O Aa Tl 



V y/ 2N-1 



A., + 



N-1,m 



N 7uT~ Aa„ N-l 

 ^2N-1 2 



N (M„„ Aa 2 T2 



/U \ Aa„ N-l 



V V 2N-1 2 



2At C "("orbK.M 



W 2N" 2 



The corresponding solution may be expressed as 



(60) 



Q N = Ti (61) 



gAt 



2N 



B N + /u) Aa. Q N 

 V y '2N 2 

 S N - T2 (63) 



At d 

 Tl = 1 + -— ' R VI , (64) 



~*" : ^ + ; f At . P M 



Ai \ Aa„ N 



'N,M 



Vm = " p n v n!m + % (66) 



V N-1,M = - R N-i n N !i + S N-1 (67) 



32 



