Given the process transfer function \[ G_P = \frac{4}{(\tau s + 1)^2} \] and the disturbance transfer function \[ G_d = \frac{2}{(\tau s + 1)}, \] what is the correct transfer function for the Feed Forward Controller for perfect disturbance rejection?
$PQ$ is a chord of length $4\ \text{cm}$ of a circle of radius $2.5\ \text{cm}$. The tangents at $P$ and $Q$ intersect at a point $T$. Find the length of $TP$.