ALF GULDBERG. M.-N. Kl. 
We deduce then 
Ou ou 
E 3 -+ I =0, 
(EBF + ED) Å 4 APT + EP (;;) =% 
(AF+ CE) — DET — ni 0, 
as the only possible combination of equations. 
That this system is relevant to the solution of the proposed problem 
may be shown as before. 
Case III. Let now E=o, F=o, G+o. System (II) (p. 16) 
then becomes 
ou 
rms 
ee 
: A 3 wee À 
The first equation gives = =o, and by substituting this value of 
u a 
in the third and fourth equations, we obtain, when © = + 0, ENO, 
os 
ee ()= 0 
We then easily derive, as a necessary condition, 
AD— HG= BC, 
and we obtain the following system of linear partial equations: 
