and 



C T ^, T 



U\t' 



C T ^a - T 



, COS a 



AB ~ ' BA 



?■ AC + " 



(28) 



The ranges for a are shown in figure 2. 



1 



c/V 

 

 .1 



::> 



X 







^ 



\ 





/| 



-^b 



1 



77 2\ 



TT 



/ 377/2 1 





^~ ^ 





Figure 2- Graphical presentalion of ihe cases (a), (b) , and (c). 



If — COS a > 1 holds, we have to distinguish two possibilities depending 



cos a > 1 



and 



we have 



^cos a — 1 



0=<a.<f, 



and with 

 the result is 



Qq '< rr/A 



AB 



--cosa— 1 iiisinaTi 



where the upper sign holds for uq >n/4 and 077/2-ao ; ^^^ •o^^'" °"s ^^olds for 

 o-Q>n/A and a<77/2- Qq or qq^^/^ and a arbitrary. From these formulas follows 



14 



