The previous Monkey Rule was about multiplication, and this one is about division. This one is notoriously complex, and no one ever just "guesses" it by trial and error, so we're just going to write it down and save you the headache:[br][br][b]Monkey Rule 7 (AKA "Quotient Rule")[/b]: To calculate the derivative of the quotient of two functions use the following formula:[br][br][math]\frac{d}{dx}\frac{f\left(x\right)}{g\left(x\right)}=\frac{f'\left(x\right)g\left(x\right)-f\left(x\right)g'\left(x\right)}{\left(g\left(x\right)\right)^2}[/math][br][br]This is probably one of the least sexy equations in all of Calculus. Even if you take a traditional algebraic course on calculus, it's not likely you'll get close to seeing the derivation of this. And what's the point? It's just a rule that tells us how to calculate derivatives. Let's move immediately to seeing it in action. Calculate the derivative of[code] felicia(x)[/code] below with the usual code snippet [code]derivative(felicia)[br][/code]

As you can see, the derivative that Geogebra calculates is exactly what the quotient rule would spit out. [br][br]Onto our last Monkey Rule!