劉亞輕 縱封磊
[摘 要]冪指函數(shù)是冪底數(shù)和冪指數(shù)都是自變量的函數(shù),通過對一元冪指函數(shù)的求導進行教學研究與分析,并推廣到多元冪指函數(shù)和n階冪指函數(shù)求導問題,進一步應用實際問題結(jié)合MATLAB數(shù)學軟件使學生對所學的知識靈活掌握并學以致用。
[關(guān)鍵詞]冪指函數(shù);復合函數(shù);偏導數(shù)
[基金項目]2017年度北京信息科技大學高教研究課題“促進學生自主學習的課程考核方式研究”(2017GJYB03)
[作者簡介]劉亞輕(1981—),女,河北石家莊人,理學博士,北京信息科技大學理學院副教授(通信作者),主要從事數(shù)學教育、可積系統(tǒng)等方面的研究。
[中圖分類號] O172.1[文獻標識碼] A[文章編號] 1674-9324(2020)45-0-02[收稿日期] 2020-05-14
冪底數(shù)和冪指數(shù)都是自變量的函數(shù),形如y=f(x)g(x)(x∈E,E是數(shù)集)的函數(shù)稱為冪指函數(shù)。冪指函數(shù)形式上既像冪函數(shù),又像指數(shù)函數(shù)。在高等數(shù)學的教學中,冪指函數(shù)的求導運算是學生學習的一個難點,對學生來說非常棘手。筆者結(jié)合多年的教學經(jīng)驗對一元冪指函數(shù)的求導進行教學研究與分析,將其推廣到多元冪指函數(shù)和n階冪指函數(shù)求導,并應用例子結(jié)合MATLAB數(shù)學軟件使學生能夠靈活掌握并學以致用。
一、冪指函數(shù)的求導法則
(一)復合指數(shù)函數(shù)求導法
將冪指函數(shù)化成指數(shù)函數(shù)的形式,然后利用符合函數(shù)求導法則。計算過程:
(二)對數(shù)隱函數(shù)求導法
四、結(jié)語
本文研究了一元冪指函數(shù)求導四種方法,證明了冪指函數(shù)求導公式,即冪指函數(shù)的導數(shù)等于相應的冪函數(shù)和指數(shù)函數(shù)導數(shù)的和。進一步推廣了多元冪指函數(shù)和n階冪指函數(shù)求導公式,應用實際問題結(jié)合MATLAB數(shù)學軟件進行驗證。本文有助于學生掌握冪指函數(shù)的求導方法,提高學生計算的準確率,使教師的教學簡單易行,有增強學生對數(shù)學的運用能力。
參考文獻
[1]賀電鵬.冪指函數(shù)求導法的探索[J].學科探索,2017:40-42.
[2]章棟恩,馬玉蘭,等.Matlab高等數(shù)學實驗[M].北京:電子工業(yè)出版社,2008.
Derivation and Application of Power Exponential Function
LIU Ya-qing1, ZONG Feng-lei2
(1. School of Applied Science, Beijing Information Science & Technology University, Beijing 100192, China;
2. Beijing Fengtai No.2 Middle School, Beijing 100071, China)
Abstract: Power exponential function is the function in which both the power base and power index are independent variables. This paper conducts teaching research and analysis on the derivation of unary power exponential function, which can be generalized to the derivation of multiple power finger function and order power exponential function, and applies to practical problems combined with MATLAB mathematical software to help students master the knowledge flexibly and apply what they have learned to practical use.
Key words: power exponential function; complex functions; partial derivative