Integration By Substitution

Specific examples were cited to analyze the mistakes and causes in the use of integration by substitution , and the general method was pointed out to avoid such kinds of mistakes in operation .

通过实例分析了在换元积分法中容易犯的一类错误及其产生的原因，指出了在解题中避免产生这类错误的一般方法。

In calculation of definite integral , beginners tend to use three methods of calculation : ( 1 ) Leibniz formula ,( 2 ) integration by substitution of definite integral ,( 3 ) integration by parts of definite integral .

在定积分计算中初学者常用的计算方法有三种：（1）利用牛顿-莱布尼兹公式，（2）定积分的换元积分法，（3）定积分的分部积分法。

The integration by second substitution is an important method of calculating indefinite integral , it has a certain application , it usually applies to calculate some integrals of irrational function .

第二换元积分法是求函数不定积分的一种重要方法，具有一定的适用范围，对某些无理函数的积分的求解通常使用该方法。