title: Haskell tuple function composition
body: <p>I have started learning Haskell from Introduction to FP using Haskell by Richard Bird, but I am stuck in proving the following: </p>
  
  <pre><code>pair (f, g) . h = pair (f . h, g . h)
  </code></pre>
  
  <p>The definitions of pair is the following:</p>
  
  <pre><code>pair :: (a -&gt; b, a -&gt; c) -&gt; a -&gt; (b, c)
  pair (f, g) x = (f x, g x)
  </code></pre>
  
  <p>Could someone point me in the right direction? Please keep in mind that I am only at the beginning. Thanks in advance!</p>