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The quotient rule says that if f(x) is defined as follows:



... then the derivative of f(x) is defined as follows:



A common way to remember this is by the phrase "Lo d hi minus hi d lo over lo lo" or "Down d up minus up d down over down down", or something similar.

An even catchier way is with a rhyme:

Lo d hi minus hi d lo,
Square the bottom and off we go!

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