Thereiore, the following equat 5 ms must be satisfied: 



fa- L<tA- lo^kf =o 



/a + l <rc = o (19) 



^e -* L(tD = o (20) 



2 <J oss 4> ■ A -<x TT ^" = ° (2i) 



2 oj coscf ' B - l6B + ~t — F -=-o ^2) 



(17) 

 (18) 



Ik 6 =o . (2h) 



Trom (2lt) and (20), it is evident that 



Solving (19), (21), (22), and (23^ in terms of A gives 



£-=-L£ttA (25) 



£ = L^A (26) 



<3-= *7^r <2oS <P A , and (27) 



F =<&&*. (28) 



