ABSTRACT
Hence (dr/ds, dr/ds) = k2. From the supposition of positiveness of k it follows that y is parametrized regularly by S. Let rr be a length of arc of y. Then the length of arc s of F can be viewed as an increasing function s = s(a) of m. The derivative of T with respect to is a unit vector, therefore from
So, in order to prove inequality (21.1) for some closed curve we must evaluate the length of its spherical indicatrix of tangents.
