(a) Show that the length of the broken line satisfies Length(L)≥ |AB|.
(b) Show that L achieves the lower bound
Length(L) = |AB|
if and only if the vertices V1,...,Vk−1 all lie on the segmentAB and appear in that orderonAB,i.e.,theysatisfyVi ∈Vi−1Vi+1forall1≤i≤k−1.
