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BELL SYSTEM TECHNICAL JOURNAL 



such a way that the boundary conditions for the cut edges are very nearly 

 satisfied. The plate formed in this way may then be considered as vibrating 

 at the required frequency /, which will then be the resonant frequency 

 desired. 



LENGTH 



Fig. 7.6 — Extensional modes with mechanical coupling 



Fig. 7.7 — Infinite strip 



Let displacements be arbitrarily chosen in the following way: 

 II = U cos kx cos (A 

 D = F sin ^.v sin (y] 



(7.12) 



