Functional decomposition vs use case
<blockquote>
  <p>Functional decomposition is not used when applied to use case
  modeling.</p>
</blockquote>

<p>This phrase is a copied one from a question paper.What is the meaning of that phrase. </p>

<p>This is not equal to the question <a href="https://stackoverflow.com/questions/947874/what-is-functional-decomposition">What is Functional Decomposition?</a></p>