HARMONIC ANALYSIS 



B, - i { - 2-069 - 0-720 cos 60 - 1-849 cos 60} 



_ f { _ O.Q69 - 2-069 cos 60} 

 6 



- -0-517 



O-OOl 



f-2Ol 



FIG. 136. 



To get A 3 and B 3 (Fig. 136). 



Then 

 and 



A 3 = 



B. 



1-201 

 6 



= 0-2 



x = 2-1 + 0-558 cos 6 - 0-517 cos 20 f 0-2 cos 30 

 + 1-532 sin - 0-091 sin 20 



where 



= -7=- if T is the periodic time. 





196. It has already been shown that between x = and x = 



y = mx= 2wi-(sin x - sin 2x + - sin 3# - sin 4>x+ . . .} 

 12 o 4 



whenwi=l, x = 2(sin x - sin 2x+ - sin 8x - sin 4>x + . . .} 

 I 2 o 4 ) 



and it is interesting to watch the development of the function 

 y = x from its component sine functions. Fig. 137 shows such 

 a development. 



