3. Consider the 1D wave equation uu(t, x) = cuxx (t, x), x = (0, L), t> 0, subject to the Neumann boundary conditions ux(t, 0) = 1 and ux(t, L) = 1, t0, and the following initial conditions u(0,x) = (x) and u+(0, x) = (x), x = (0, L), for some given functions & and . (12) (13) (14) Complete the first three steps in constructing the solution to the above IBVP using the method of separation of variables.