792 



(f z=z Acos — X -)- B sin — x -\- C 

 a a 



01' according to the above 



^. ^ ay p 



ff = I — cos — X — sin ~ X -\ \ \ . (17) 



'' - , pi a 



sin — 

 a 



Introducing this result into the second equation, we obtain 



E cos pt =^ RIcos {pt f /i) -| sin (pt -f ^) 



QP 



j 1-cos— ] 

 a pi a K a J 



- -sin"-- -^ f + / .(18) 



pap pi 



sin — 



a 



Now take 



('-"^?) 



HU I a , pi ^ ..^ 



(jpR \ p a pi 



sin — 

 r 



then w^e find 



1 / r. . (l—cos^lX 



I / H' / a p a\ a J y 



Ecospt—J \ R^ -] sin- I ^ ^ 4- I cos{pt+ii-a) 



1/ q'p' y p a p , p J 



J sin — I 



a 



From this we find for the retardation of phase, ji = « ; and for 



the amplitude of 1 



E 



/ = - 



r 



where r represents the square root in the second member. The 

 current / being found in this way, ?/ can be determined from (17). 



When L does not vanish, we can suppose y and I to depend on 

 e'P'- ; and finally taking the real part, and following the above method 

 we find the values of y and /. 



If we express y by (2), the solution can also easily be found. We 

 then have 



4HJ 



ffg = . 



s:;T{n/—p'-) 



Substituting this into tfie second equation of § 3 (where zero has 

 been replaced by Ecospt) we find 



