Multilayer Coils ivith Square and Circular Section. 973 



By means of f{8) and <£(<9), V may be expressed by the 

 formula 



v=-£|[/(0)+<K0)]. 



Fig. 8. — Graph of the function /(»). 



Fig. 8a.-- Graph of the function <f)(G). 



The graphs of f{6) and <j>(6) are shown in figs. 8 & 8 a. 

 Remembering that the series 

 4 

 (cos# — ^ cos 30 + 3 cos 50— . . .) 



TT 

 IT 



71" 7T" *TV ♦ j 7T 



is 1 from — ^ to + „ and — 1 from — to — (as may be 



1 -f- j; 

 seen by Fourier's theorem or by expanding log, '), it 



is found ot once by integration (which may be shown to be 

 legitimate) that 



0) = i(sin 0-isi» 3^ + isin 56-.. .) 



_ 4 " ( -)"sin(2w + l)<9 



(?) 



