Tractrices can be fun! * Rotate the graph of y = tractrixfunction(x) for x > 0 about the x-axis, and you get a smooth maximal surface among all such surfaces of constant Gaussian curvature = -1 that are embedded in 3-space. * Imagine, for each c >= 0, a rigid rod r(c) in the first quadrant of length = 1 with its lower endpoint lying on the x-axis such that a) r(0) is the segment from (0,0) to (0,1), and b) r(x_1) and r(x_2) are disjoint if x_1 ≠ x_2. Then among all arrangement of these unit segments according to a) and b): What is the least angle that the segment r(x) makes with the positive y-axis? That turns out to be the angle made by the tangent line to the tractrix. —Dan ----- https://en.wikipedia.org/wiki/Tractrix http://mathworld.wolfram.com/Tractrix.html http://mathworld.wolfram.com/PursuitCurve.html ... ... -----