( 392 ) 
u 
d 
_f o dh is i wu + hy) du = — ch fa ‘= w(u + hy) du = 
ay dh. dh 
0 “u—0 == 1) 
eS fa fame LU 
u—0 
We put w(«) du = — da (u) and suppose, as is usually done that 
a(e) is equal to zero. The latter expression may be transformed 
into : 
do if dy on do 
— 0 Th. 7 (hy) dh, = = den hy 2) — 0 bares A w (hy) dh 
0 0 0 
The integrated term is zero for the two limits. 
d 
foon 2 Ti ges (u + hj) udu= — 0 airs d. 77 (u + hj) = 
u=0 0 u=0 
do ; 
=—¢ TE. 5 E 7 (u + zl 4. 05 —> fai m(u+h)du... (1)(3) 
dh2 
0 u—0 0 . v=0 
Here too the integrated term is zero for the two limits. 
We put zr (#) dr== — dy(xr) and suppose as usuai that 7 (0) — 0. 
The latter expression may be transformed into: 
un 9 u 
do “ „de 
zoa har ee ete ze 4 I,)|= 
SN dh? AT ~ 
0 ved 0 u—0 
Po P Gee 
Ser [thy ai, =e a 7, x(h)| + est Jura) dh. 
TN > dh? L : anes 
0 
0 
The integrated term is zero for the two limits; so the expression 
becomes: 
‚Pe h,? do by do “hy? 
= fran toe a In og] ten w (Iq) dn 
0 
