International Journal of Mathematics and Mathematical Sciences
Volume 7 (1984), Issue 1, Pages 117-130
doi:10.1155/S0161171284000132
    
    
    Some isometrical identities in the wave equation
    
    Department of Mathematics, Faculty of Engineering, Gunma University, Kiryu 376, Japan
    
    
    
    Received 30 April 1983
    	
    
     
    Copyright © 1984 Saburou  Saitoh. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
     
    
   
 
Abstract
We consider the usual wave equation utt(x,t)=c2uxx(x,t) on the real line with some typical initial and boundary conditions. In each case, we establish a natural isometrical identity and inverse formula between the sourse function and the response function.