360 Prof. D. N. Mallik on 
--i^lT-o+my--) 
dy' 
{h-h'y 
_ 1fi , _a a r B 5" '"<' « 2 " • ^ 2 '" \ 
/_a \ 2 " _ Y a. v*" -1 ' 1 
x \d«7 \d?<7 v^+i' 2 +('*-/<') 2 ' 
where 
( ^-Y 1 1 s C a ' dx 
\aW </ a ' 2 +v 2 + (h-h'y Jo x /z 2 +b 2 +{h-h f y c *' 
which can be written down from (1) and (2). 
If the distance between the planes is small = d, 
a^ a i _ _} , 
~dh ' -dh' Va'H^^ + CA-Af " (a/* + b'* + d?)l ""*&• 
and 
{ a 2n fr2m 
** (2n + l)l(2m+l)l 
/ a v 9 "- 1 / a y— * i 1 
X \da'J \db' ) (a! 3 + b'*+d*)* J ' 
which is directly suitable for calculation if the terms 
decrease rapidly (the first three terms involving integrals 
which can be easily evaluated). 
The final result can, however, be written down : — 
For we have 
(^ a -XF(a /2 ) = (2a / y . F'(a !2 ) +^-^ (2a') r - 2 . F<- %&) + . . . 
Put w , 2 . 1 1 
F(a) " Va' 2 + ^ + (A-/0 2 "p SaJ; 
then 
and 
,,„_ 1.3..(2r-l) , „, J, 
/> 2 
FV 2 ) = •*••£' ' ' (-1)' • 3+i' 
