Using these definitions we find 



W,-- 





2- qA 2ap-P «^vi 







Putting in the identities we have: 







S \ ^N U 2 -©- 1 -i.(s \v^^ve ■*- <^OS.^e) 



-([ t.a'"'''-'''* W& ^- ^-"i ^^-^^-^ ^-^-^ 



23 



