Looks like there's a bug in the quotient rule.
Last I checked, the derivative of (x/1) is not (1-x)/x^2 .<p>Screenshot: <a href="http://i.imgur.com/bYiDjAZ.png" rel="nofollow">http://i.imgur.com/bYiDjAZ.png</a><p>Fix: <a href="http://pastebin.com/raw.php?i=NfBiqia0" rel="nofollow">http://pastebin.com/raw.php?i=NfBiqia0</a>
i hate to be that guy, but.......<a href="http://www.derivative-calculator.net/" rel="nofollow">http://www.derivative-calculator.net/</a>