Question

prove that in a tree every vertex of degree greater than one is a cut vertex

Answer 1

HINT: Think about the longest path P=v0,v1,…,vn−1,vnP=v0,v1,…,vn−1,vn. The vertices v0v0 and vnvnboth have to be end vertices of TT, so what can you say about v1v1 and vn−1vn−1