12 
After rearrangement of the 
  
dx da, 2x 
— rm —— l— 1 = 
S. +7 
da; 3x 
+ |—4+- P + 
t h 
x x 
iy Piles aii 1 dz" — or 21 " 5 ; 
dx A ) + dx + (dy dy”) y | j 
dy da, 2 T 
—--—-i2.-—.— 
S 5 b b 
dx, 3y 
2.2L 2 
5 b 
: dy, ee 234 " 
5 b 
y 
— (dx' — dx") — 
(dx dx") b 
expressions (28) and (29) we find 
y da, 3x 
b 5i "5 
y da. 2x 
v ped i LP oars et 
bj] 5 b 1 
dy. 2% 
11° + 7 — 
5 b 
dx, ( 3y 
"lli 10 33. 
5 b 
x 
— dy" |— — 1| + dy’ 
C b © 
b 
y 
D 
y 
— fi 
b 1 
y 
DI. 
x 
+} (34) 
x 
b N 
x 
b T 
Applying the special law of error propagation to the expressions (34)— 
(35) we find 
Ou 1 2r y) 
—— E eem 4 a 1 Se 
8? 25 A b 
C 1 2 x \? 
Qu = [. (2 + ^y + 3 + 
Ye | - 
S? 25 |