1. The problem statement, all variables and given/known data Show that sines and cosines are the solutions of the differential equation f''(x) = (-σ^2)f(x) What if a boundary condition is included that g(0) = 0? 2. Relevant equations f''(x) = (-σ^2)f(x) 3. The attempt at a solution Plugging in sin(σx) and cos(σx) yields an equality therefore the expression is true. I'm just confused about the boundary condition. If g(0) = 0 then only the sin(σx) works, correct?