# Differentiate quaternion differential equation

I'm reading at the moment this paper, but I'm not clear with some steps the do:

On page 5:

• When I differentiate $$\dot{\mu}$$ by $$mu$$ there should be also $$-M_q w_q$$ in the A matrix at position 0,0? They have only $$-\hat{I}_{w\times}$$ there.

• How do they get $$-\hat{I}_{a\times} R(\hat{q})$$ as solution for $$\frac{d \dot{v}}{d \mu}$$ ?

Do anybody know how I derive this linearization?