Quotient Rule

In calculus, the quotient rule is a method for finding the derivative of a function that is written as the ratio of two differentiable functions. For a function h(x) equal to f(x) divided by g(x), where g(x) is never zero, the rule gives its derivative as f prime of x times g of x minus f of x times g prime of x, all divided by g of x squared. Students often remember the pattern as low d-high minus high d-low, over low low, and the rule lets a quotient be differentiated directly, without first rewriting it in another form; it can itself be derived from limits, implicit differentiation or logarithmic differentiation.