|
In mathematics, Fermat's theorem (also known as Interior extremum theorem) is a method to find local maxima and minima of differentiable functions on open sets by showing that every local extremum of the function is a stationary point (the function derivative is zero in that point). Fermat's theorem is a theorem in real analysis, named after Pierre de Fermat. By using Fermat's theorem, the potential extrema of a function , with derivative , are found by solving an equation in . Fermat's theorem gives only a necessary condition for extreme function values, and some stationary points are inflection points (not a maximum or minimum). The function's second derivative, if it exists, can determine if any stationary point is a maximum, minimum, or inflection point. ==Statement== One way to state Fermat's theorem is that whenever you compute the derivative of a function's local extrema, the result will always be zero. In precise mathematical language: :Let be a function and suppose that is a local extremum of . If is differentiable at , then . Another way to understand the theorem is via the contrapositive statement. If the derivative of a function at any point is not zero, that point is not an extrema. Formally: :If is differentiable at , and , then is not a local extremum of ''f.'' 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Fermat's theorem (stationary points)」の詳細全文を読む スポンサード リンク
|