64 A NEW METHOD OF DETERMINING 
and hence 
C2 3 om (pi 1 : : 3 
=o Bre SG ree seit ‘ f _/ ‘ 7 IV 
drdZ 2 1+m [ ae al eu a su (f 1 ) 
HQ nv i 1 : : dQ 
7 ete ea sib [a — — | sin J.rsin TI — 
drdZ’ 4 iba AP | (f+ ) da’ 
dQ 
becomes 
the latter of which, by means of the expression for 77, 
RD Vo SS 1 | 2 . Sab ss Po 
= 2 aap 7 3x| Sm Ir sin (f + I) im I va Sin (PE TD) 
The expression for A’ also gives 
(P—rr Hy (ry 7S fe i 
OM Sr ah 44 2H 44? 
by means of which we find 
/ 
5 AQ _aQ m | 3(r?—r*)? r? 1 m r 
ee = eal eee oe le 
ip Ts 1m 44 1+m 7” 
If we put, for brevity, 
(T), = = sin [ ey sin (iF? si Il’) 
(ry = sin (2) (2) sin (FED 
(= z cos 2 (2) 
