The following differential equation governs the evolution of variable \(x(t)\) with time \(t, t \geq 0\). \(\frac {d^2x}{dt^2} + 4x = e^{-t}\) Given the initial conditions \(x = 0\) and \(\frac {dx}{dt} = 0\) at \(t = 0\), the value of \(x\) at \(t =\frac {\pi}{8}\) is _____ . (Rounded off to 3 decimal places)