Show that the helicopter model defined in Example 2.1 is linear if and only if the initial angular velocity y(0) = 0. (b) Show

Show that the helicopter model defined in Example 2.1 is linear if and only if the initial angular velocity θ ̇y(0) = 0.

(b) Show that the cascade of any two linear actors is linear.

(c) Augment the definition of linearity so that it applies to actors with two input signals and one output signal. Show that the adder actor is linear.