Suppose that a vector function r(t) is parametrized with respect to arc length s, creating a new function r(t(s)).
Which of the following is/are TRUE?
a. The graph of the arc length function s(t) can be decreasing.
b. Both r(t) and r(s) trace out the same curve.
c. ds/dt = k, where k is a constant, then s(t) = kt.
d. The distance along the curve between s = 6 and s = 9 is 3.