Solve the boundary-value problem k * (d²u/dx²) + 2 * (du/dt) = 0, 0 < x < 1, t > 0. Subject to the boundary conditions u(0, t) = 0, (du/dx)² + x * (du/dt) = h(u(1, t) - 2 * u(0)), h > 0, t > 0. Also, given the initial condition u(x, 0) = f(x), 0 < x < 1.