340 Mr. R. Hargreaves on Radiation 



(ii.) For B 2 = 4:finn ,l l(fin + n") 2 ) the work is more troublesome. 



Put 2ny=s/jJ^l{l-f), 2 f in" 2/ =^JJ^l{l+f) ) 

 and write 



then 

 „_ C HfinWdn _ /*2 f 1 (l-y^dy 

 1 "Jo (/"* + n") 2 Ai»-lJ lb y , (o»-y s )» 



^"^Jy. * c "y °y c Q {c 2 -f) c\c*-y 2 f$ 



yy 2 . 2 i i j.^ 8 - 1 ! /2 ax ; (c 4 -i) 2 i l 



(^+i)V-i) (/* 2 +i) 2 0*-i)(/*+i)V 2 +i) 2 



+ Am 2 -1) 2 1o /*+!_ VQ*' + 1) , 



where 



, 3c 4 ~2c 2 -2-c- 4 + 2c- 6 (c 4 -l) 2 (c 2 -l) 



C 2 -*/ 2 C 4 (c 2 -2/ 2 ) 2 ' 



(C 2 +1)(^~1) 2 (5C 4 + 2 C 2+5) 1 C+y (C 4 -1)2( C 2-,1) y 



4 C 7 g c-y 2c 6 c 2 -z/ 2 ' 



giving 



bji- ^ 2 r "- 1 +^ ,+3 + (^+i)'^-ix^-3) 



152 ""2(^ + 1)13(^ + 1) % 2 -l 0* 2 + l) 3 



Qu + 1) 4 8> 3 1 4iuV + 12iU 4 + 2) 



b> 2 +l) 2 (^ + 1)3( JU 2_ 1) J 3 ( iL1 2 + l)3( iU 2_ 1)| 



