【正文】
,所以,因為二階可導,所以在點處二階泰勒公式成立,在與之間, 因為:,所以,所以,即。 分析:在上二次可微,且最小值,所以在內(nèi)一定有極值點,該點的導數(shù)為,題中可知二次可微,從這點我們可以想到使用泰勒公式,而要證明的結(jié)論中右邊是一個常數(shù),故選在最小值點處泰勒展開。 利用泰勒公式證明不等式及中值問題 如果函數(shù)的二階及二階以上導數(shù)存在且有界則用泰勒公式去證明這些不等式。 例3 求極限。 例2 求極限。 例1 求的極限。 帶有積分型余項的泰勒公式 如果函數(shù)在點的某鄰域內(nèi)有階導數(shù),令,則對該鄰域內(nèi)異于的任意點,在和之間至少存在一個使得:其中就是泰勒公式的積分型余項。我們可以使用泰勒公式, 來很好的解決某些問題, 如求某些極限, 判斷級數(shù)及積分的斂散性, 求函數(shù)的高階導數(shù)、證明中值公式、。s formula in calculating the limit, the series and the in tegral of the divergence and judge, the proof of inequality and median formula and solving the problem of derivative function.Key words: Taylor formula。關(guān)鍵詞:泰勒公式;應用;級數(shù);斂散性 Taylor formula and its application Student: Lu LiangrongInstructor : Xiang WeiDepartment of Mathematics and Computational Science: Huainan Normal UniversityAbstract:Taylor formula in mathematical analysis is a very important content, not only in theory occupies an important position, and in the limit, to prove inequality, discuss the convergence and divergence of ser ies and integral of function, high order derivative, mean value formula for solving the problem of proof, derivative and approximate calculation are an extremely important role. In this paper the above listed several roles are discussed, but focuses on Taylor39。 Convergence and divergence前言 泰勒公式是數(shù)學分析中一個非常重要的內(nèi)容,微分學理論中最一般的情形