Section 13.2
In this worksheet we just give one example of the tangent vectors moving along a curve.
Example: Consider the curve ${\bf r}(t) = \langle t, \cos (t) \rangle$. The first animation gives the vectors ${\bf r}(t)$ as $t$ moves as red arrows. The tangent vectors are given by the green arrows.

It may also be easier to see the tangent vectors ${\bf r'}(t)$ without the vectors ${\bf r}(t)$ as well. That is given in the following animation.
