共查询到20条相似文献，搜索用时 62 毫秒
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微积分中 ,分部积分法是一种重要的基本积分方法。它解决的对象是被积函数为两个不同类型函数乘积的积分。当乘积中含有对数函数因子、三角函数因子、反三角函数因子和指数函数因子时 ,用分部积分法最为奏效。它的一般步骤是 :1.凑微分 :把被积函数中的一部分和ｄｘ凑成ｄｖ ,使积分变成∫ｕｄｖ型 ;2 .代入公式 :∫ｕｄｖ =ｕｖ -∫ｖｄｕ ;3 .求出∫ｖｄｕ后 ,便可求出∫ｕｄｖ。上述三步过程可综合简述为如下分部积分公式 :∫ｕｖ′ｄｘ =ｕｖ -∫ｕ′ｖｄｘ抓住分部积分公式的本质 ,便可将此方法列表 (表 1) :首先将被积函数分为ｕ和ｖ… 相似文献
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分部积分公式:∫udv=uv-∫vdu,初看起来很简单,但在具体解题过程中,分不清哪部分为u,哪部分为dv,以致解题失败.用分部积分法求不定积分关键在于:恰当地将被积函数分成两部分,其选择u和dv的原则:①积分容易者选作dv;②求导简单者选作u,在二者不可兼得的情况下,首先保证的是前者.…… 相似文献
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胡必文 《湖南科技学院学报》2005,26(11):35-36
本文将分部积分法则∫udv=uv-∫vdu进行了推广,得到了被积表达式是三类及其以上的不同函数乘积形式积分的分部积分一般法则,并给出了一个实例说明它的就用. 相似文献
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杨萍 《开封教育学院学报》1997,(1)
本文讨论了不定积分中分部积分法的一般公式:∫uv’dx=uv-∫u’vdx.当积分∫uv’dx不易求解时,我们适当地u和v,把积分∫uv’dx转化为比壮容易求解的积分∫u’vdx. 相似文献
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分部积分法应用的总结 总被引：1，自引：0，他引：1
周宏辉 《中国校外教育(理论)》2009,(6)
∫udv=uv-∫vdu称为分部积分公式,它可以将求∫udv的积分问题转化为求∫vdu的积分,当后者这个积分较容易时,分部积分公式就起到了化难为易的作用.由此可见,用好分部积分法关键是恰当地选择好u和dv,一般要考虑如下两点: 相似文献
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贾贞 《长江工程职业技术学院学报》2001,18(2):52-53
在高等数学中 ,我们常常遇到这样一类求积分题 :如∫ｘ2 ｅ2ｘｄｘ ,∫ｘ3ｃｏｓ5ｘｄｘ等 ,这类积分的一般解法是采用分部积分法 ,而且要反复多次使用分部积分公式 ,特别是当被积函数的前一个因子的次数越高时 ,使用的分部积分步骤越多 ,运算越麻烦。下面将给出几个超越函数求积分的公式 ,对于解决这类积分非常实用。公式 1.若 ｐ(ｘ)为ｎ次多项式函数 ,则有 :∫ｐ(ｘ)ｅａｘｄｘ =ｅａｘ ｐ(ｘ)ａ - ｐ′(ｘ)ａ2 +… +( - 1) ｎｐ(ｎ) (ｘ)ａｎ +1+Ｃ (ａ≠ 0 )证明 :∵ ｐ (ｘ)为ｎ次多项式 ,∴ ｐｎ +1(ｘ) =0 ,∴ ｄｄｘ ｅａｘ ｐ(… 相似文献
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全日制十年制课本指出:“用分部积分公式的关键是u与dv的选择要得当,否则可能会使问题愈来愈繁。”分部积分公式总是适用于被积函数是两个函数乘积的积分。这两个函数往往是多项式(包括单项或常数)、正弦函数、余弦函数、指数函 相似文献
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定积分概念是用极限定义的,有很强的思想性．按定积分概念,用计算定积分的方法求解无限和的极限或数列极限是教学中的一个难点,这里应对难点给出一个易掌握的处理方法．分部积分“分部”的意思是把两个函数u（x）和v（x）的乘积uv拆分为不定积分∫udv与∫vdu两部分的和,即uv=∫udv＋∫vdu,其中∫e^ax sinbxdx、fsin（lnz）dx这一类的分部积分是教学中的又一个难点,处理这类不定积分方法的数学依据是这时的fudv和fvdu之间有一个容易得到的形如λλudv＋μfvdu=w（x）（λ,μ为常数,λ≠μ）的线性关系． 相似文献
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袁莉 《遵义师范学院学报》2007,9(2):87-88
本文利用和差变换公式,对分部积分公式进行了推广,得到函数u(x),v(x)在区间[a,b]上可导且b!au(x)dv(x)存在的条件下分部积分公式仍然成立,并结合数学分析教材中所给出的可积函数类,得到相应的两个推论. 相似文献
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《南昌教育学院学报》2015,(6):69-73
文章讨论无穷积分∫_a(+∞)f(x)dx的被积函数f(x)当x→+∞时的极限情况。方法:利用函数f(x)在[a,+∞)上一致连续的一些性质、结论和一些新颖的实例。结果:给出了无穷积分∫_a(+∞)f(x)dx的被积函数f(x)当x→+∞时的极限情况。方法:利用函数f(x)在[a,+∞)上一致连续的一些性质、结论和一些新颖的实例。结果:给出了无穷积分∫_a(+∞)f(x)dx的被积函数极限limf(x)x→+∞的一些条件及其证明。结论:若无穷积分∫_a(+∞)f(x)dx的被积函数极限limf(x)x→+∞的一些条件及其证明。结论:若无穷积分∫_a(+∞)f(x)dx收敛时被积函数极限为零,必须附加一定的条件才能成立,这与数项级数和函数项级数收敛时一般项趋于零是有差别的。 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
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Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献