A well-known boundary value problem requires unusual eigenfunctions

Yuriy Sosov, Constantine E. Theodosiou
2004 American Journal of Physics  
The Sturm-Liouville problem for the equation d 2 X/dx 2 ϩ 2 Xϭ0 on a closed interval with general unmixed boundary conditions leads to periodic, linear, and exponential eigenfunctions. However, examples of physical situations where different types of these eigenfunctions are employed together in a general solution are difficult to find. We present a physical problem of this type.
doi:10.1119/1.1629084 fatcat:xvxqrvjw7vgvzhbkcscxrb5pvm