## psk981 2 years ago consider a boundary value problem y"+ky=0, y(0)=0, Y(pi/2)=0. is it possible to determine the values k for trivial solutions. (b) non-trivial.

1. malevolence19

$y''+ky=0 \implies y=A \cos(\sqrt k t)+B \sin(\sqrt k t)$ From here you can plug in the initial conditions

2. across

Since the boundary conditions are homogeneous, your non-trivial solution (the case $$k>0$$) will be a Fourier sine series. For $$k\leqslant0$$, you'll get trivial solutions.