HARMONIC ANALYSIS 



ays 



(2) Now A 2 = -\y sin 20 d0, and B 2 = - f y cos 20 



TCJo TTJo 



V.-V, 



FIG. 128. 

 Hence A 2 = - (sum of the ordinates of the 0, y sin 20 curve } 



and B 2 = -{sum of the ordinates of the 0, y cos 20 curve} 

 or A 2 = - {y sin + y sin 60 + y z sin 120 + . . . T/ U sin 660} 



660} 



FIG. 129. 



If from the point O radial lines are drawn at intervals of 60 

 d the ordinates y , y lt etc., are measured along these lines. 



