title: Use python to calculate a special limit
body: <p>I want to calculate this expression:</p>
  
  <pre><code>(1 + 1 / math.inf) ** math.inf,
  </code></pre>
  
  <p>which should evaluates to e. However Python returns 1. Why is that?</p>
  
  <p>=====UPDATE========</p>
  
  <p>What I want to do here is to derive the effective annual rate from user's input, APR (annual percentage rate).</p>
  
  <pre><code>def get_EAR(APR, conversion_times_per_year = 1):
      return (1 + APR / conversion_times) ** conversion_times - 1
  </code></pre>
  
  <p>I would want this expression to also apply to continuous compounding. Yes I understand I can write if statements to differentiate continuous compounding from normal cases (and then I can use the constant <code>e</code> directly), but I would better prefer an integrated way.</p>