Find the Transfer Function of the following differential equation, in which $y$ is the output, $r$ is the input, $\alpha_1$ to $\alpha_4$ are four estimated coefficients, and the other coefficients are exactly known. Then find the steady state gain. Work with the notation given; there is no need to force this into a generalised form. $\frac{d^4y}{dt^4} + \alpha_1\frac{d^3y}{dt^3} + \frac{d^2y}{dt^2} + \alpha_2\frac{dy}{dt} + 5y = \alpha_3\frac{dr}{dt} + \alpha_4 r$