title: How to use master theorem to calculate recursion, divide and conquer
body: <p>I want to calculate Θ() </p>
  
  <pre><code>Given T (n) = T (n − 1) + n^3
  </code></pre>
  
  <p>I cannot apply master theorem rule directly, because I don't know what b is, so how to derive the Θ() ?</p>