title: Prove the height of binary tree is lower-bounded by lgn
body: <p>The following is a homework question.  I don't like posting questions without having some evidence of what I tried.  Unfortunately, at my University my professor is Chinese and his lectures are not easy to understand.  So I went to the tutoring center.  The tutors there were stumped (they're international students who never actually took this class at the University).  So after two days of going to the tutor dept. and not a single tutor was able to help me, I've resulted to Stack Overflow.</p>
  
  <p>The book we are using is <a href="http://ressources.unisciel.fr/algoprog/s00aaroot/aa00module1/res/%5BCormen-AL2011%5DIntroduction_To_Algorithms-A3.pdf]" rel="nofollow noreferrer">Introductions to Algorithms</a></p>
  
  <p>I've read through the chapter and I'm not able to figure out how to start and finish this.</p>
  
  <p>Can someone please help me with this answer?</p>
  
  <p><a href="https://i.stack.imgur.com/vv9l6.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/vv9l6.png" alt="enter image description here"></a></p>