title: Idetifying equivalent regular expressions
body: <p>I am revising for am exam and one of the topics is regular expressions. </p>
  
  <p>A past exam paper has the question</p>
  
  <blockquote>
    <p>Which of the following regular expressions are equivalent? Explain
    your reasoning. [8 Marks]</p>
    
    <p>(i) (a+b)* b (a+b)* b (a+b)* </p>
    
    <p>(ii) a* b a* b a*</p>
    
    <p>(iii) a* b a* b (a+b)*</p>
  </blockquote>
  
  <p>I think its a trick question and the answer is none because </p>
  
  <p>i will accept aabaabaabaabbaabaabaabaabbaabaabaabaab but ii and iii wont</p>
  
  <p>then because ii can only accept 2 b's maximum and iii can accept 2 b's as a minimum. </p>
  
  <p>Am I correct or have I got this completely wrong? </p>
  
  <p>I have e-mailed my lecturer for help but had no reply so I'm hoping someone here can help. </p>
  
  <p>Thanks.</p>