FBOPoemoNS wraonxo Arnurnov. 



Uc arc. Resolve the mtt nation of the arc 

 icle at ili.- jn.lr u initial 1m. , and at right 



: Uesc two components 



arc considered extends from $ - to - o. Hence, 

 hypothesis, 



Put $(0) for - . thus we hare 



I V (&) in 9 dB = tan " l (0) cos <#. 



lation is to hold for all values of a, and there- 

 to may d i t ]\ m t U respect to a. Thus, 

 'e-yra/ Calculus, Chnj we have 



d> (a) sin a - sec* I 6 (0) cos 6 dO -- tan 4(a)oosa; 



f \ f > ^f ^ 



V| 



lore 



2^> (a) ^sina - tan ? cos aj cos' ? - J <f> (0) 



that is </>(a)sina | <f>(0)co*0<W. 



J 



rcntiatc again with respect to a; thus 

 </> (a) cos a + sin a . (a) - ^ (3) oosa ; 



<5 (a) 0. 



