past chapters come under the properties of this particular integral. 
The form of Eo( 39), for example one is given by equation 
(9.29). W(p,8) is zero. E,(p,0) is indicated schematically 
by the little polar coordinate sketch on the left. Graphed as a 
surface in the three dimensional ,0,E,(,0) space, E5(p ,e) 
would look like a vertical cliff along the curve pm = Ho be- 
tween © = O and @ = 7/2, and the curve 9 = 0, between M= Hy 
and = 00. There will be a sharp corner at the point (#,,0). 
; would exist to the upper right behind these 
A plateau of height A 
two curves, and E,(#,®) would be zero everywhere else. 
Now consider a partial sum such as equation (9.22). For any 
net, a portion of the net will look like the magnified part shown 
in the plate. There will always be an area element in the p ,0 
plane which encloses the point (70). For this particular net, 
the appropriate corner points are given by C5528) 9 CH 5440982) 
(4554028 omeo) and (5518 om40) in a counterclockwise order. The 
Square root of the appropriate term in the partial sum then has 
the value, A, for this set of four points as shown by equation 
(9.31). All other elements in the net contribute nothing to nee 
partial sum. For example, the contribution of the element to the 
right of the one just considered, yields a value of zero as shown 
by equation (9.32). Consequently, for this particular partial sun, 
the value of the partial sum is given by equation (9.33). There 
is always some set of four net points such that equations (9.34) 
and (9.35) hold, and as A, and A,° go to zero, the final re- 
sult is equation (9.36). Consequently, example one is simply a 
single sinusoidal wave traveling in the positive x direction of 
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