title: Implementing the derivative in C/C++
body: <p>How is the derivative of a <code>f(x)</code> typically calculated programmatically to ensure maximum accuracy?</p>
  
  <p>I am implementing the <a href="http://en.wikipedia.org/wiki/Newton%27s_method" rel="noreferrer">Newton-Raphson</a> method, and it requires taking of the derivative of a function.</p>