A goat is tied by a tether of length L to a circular silo of radius r. If the tether is wr...

A goat is tied by a tether of length L to a circular silo of radius r. If the tether is wrapped against the silo so that the goat initially is at the point (r, 0) and the goat walks so as to unwind the tether and keep it taught, find a parametrization for the goat’s path. See Figure 1.

Figure 1