On pg. 96 of No-Nonsense Classical Mechanics, the author asserts:
The trouble I am having is with the highlighted portions. In particular, how do we derive a general formula for velocity $\dot{q}$:
$$ \dot{q} = \dot{q}(q, p) $$
from the formula for "generalized momentum" in the Lagrangian setting:
$$ p = \frac{\partial L } { \partial \dot{q} } $$
?
