Hi...I'm wondering if infinite set theory has any place in finding limits. Is there any way that tabling elements of sets can find you the answer to a limit question?
In set theory by itself, there is no such thing as "limit". For the concept of "limit" to have any meaning, there has to be a topology defined for the sets.
I'm reviewing Meirovitch's "Methods of Analytical Dynamics," and I don't understand the commutation of the derivative from r to dr:
$$
\mathbf{F} \cdot d\mathbf{r} = m \ddot{\mathbf{r}} \cdot d\mathbf{r} = m\mathbf{\dot{r}} \cdot d\mathbf{\dot{r}}
$$