pf ^ W^ dz = -i ^Cl + jp)^ Pf g(koV^ a^ e"^^"" , CA-97) 

 



which is to be compared with the term retained, i.e., pg a . 



Thus, for the term given by equation (A-97) to be negligible we 

 must require that 



i- fCk h )^ << 1 , (A-98) 



which for values of f greater than unity is a more severe requirement 

 than that given by equation (A-53) . Thus, for values of kghQ |^^ 0.5 and 

 f ^4, which are reasonable values, the inequality (eq. A-98) is only 

 approximately satisfied. 



123 



