Computer · Control Systems - Steady-State Error

A unity-feedback system has a forward path consisting of a gain of 10 followed by a plant G(s) = 1 / [s(s + 10)]. A load disturbance d(t) is summed at the plant input (after the gain of 10). The error is defined as e(t) = r(t) - y(t). With the reference set to zero (r(t) = 0) and a unit step disturbance D(s) = 1/s applied, find the steady-state error e(∞).