wa can express G~ as 



*/2 



G 3-"f 



i 



[R + (**)S + R +~( 2 5)s]d-0, M +''" W - Z ° (47) 



o+, 25- > 



The derivatives of G., can be easily expressed fron Equation (38) 

 BO. 



ox 



■ i u coaS G, 



(48) 



dG, 



oy 



■ i u sinQ G, sign(u) 



(49) 



5G3 



5s 



u G. 



(50) 



where 



sign {in) • 1 for w - u + 

 ■ -I (0 ■ w_ 



(51) 



15 



