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妙用“假设法” 巧解数学题——用“假设法”解决小学中高年级数学实际问题的策略 被引量:3
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作者 王姜玲 《小学教学研究》 2019年第27期26-28,共3页
在解决数学问题时,巧妙运用“假设法”可以找出隐藏的条件,理顺数量关系,是帮助学生快速、准确地解决问题的一种敏捷性思维。因此,在小学中高段数学教学中,教师要鼓励学生大胆假设,经过合理的推理与演算,提高学生解决实际问题的准确性... 在解决数学问题时,巧妙运用“假设法”可以找出隐藏的条件,理顺数量关系,是帮助学生快速、准确地解决问题的一种敏捷性思维。因此,在小学中高段数学教学中,教师要鼓励学生大胆假设,经过合理的推理与演算,提高学生解决实际问题的准确性和效率。 展开更多
关键词 “假设法” 小学中高年级 数学实际问题 解决策略
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例析“假设法”解浮力题 被引量:1
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作者 赵贺春 《中学理科(综合)》 2005年第7期49-49,共1页
【例1】(2004年北京市中考题)如图所示,一个半径为r,质量为m的半球,放在容器内,半球的底面与容器底部紧密接触,容器内装有密度为p的液体,液面高为H,己知球体体积公式是V=4πr^3/3,球表面积公式是S球=4πr^2,圆面积公式是S圆... 【例1】(2004年北京市中考题)如图所示,一个半径为r,质量为m的半球,放在容器内,半球的底面与容器底部紧密接触,容器内装有密度为p的液体,液面高为H,己知球体体积公式是V=4πr^3/3,球表面积公式是S球=4πr^2,圆面积公式是S圆=πr^2,则由于液体重力产生的对半球表面向下的压力为_____. 展开更多
关键词 “假设法” 浮力题 容器底部 面积公式 液体重力 体积公式 球体 中考题 北京市
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巧用“假设法”解题例举
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作者 张尖 《小学教学参考(数学版)》 2006年第7期75-76,共2页
关键词 “假设法” 解题思路 巧用 例举 数学思维方 已知条件 数学问题 关系比较 常规方 数量关系
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用“假设法”巧解热平衡问题
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作者 鲍连富 《数理化学习(初中版)》 2003年第8期31-32,共2页
各种物理考试中,常遇到关于热平衡问题的计算:几种物质混合,通过分析哪些物质吸热,哪些物质放热,然后利用Q吸=Q放列方程解答.若只两种物质,自然不存在困难,若不同温度的物质有三种甚至更多,采用直接分析,往往出现过程复杂、计算量大等问... 各种物理考试中,常遇到关于热平衡问题的计算:几种物质混合,通过分析哪些物质吸热,哪些物质放热,然后利用Q吸=Q放列方程解答.若只两种物质,自然不存在困难,若不同温度的物质有三种甚至更多,采用直接分析,往往出现过程复杂、计算量大等问题,此时利用“假设法”,假设一个特殊的过程,可使问题变得简单明了,收到出奇制胜的功效。 展开更多
关键词 “假设法” 热平衡问题 初中 物理
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借助“假设法”进入学科认知情境
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作者 李倩 《中学语文教学参考》 2022年第15期10-11,共2页
借助“假设法”,能够引领学生进入学科认知情境,进而促进学生语文核心素养的构建。文章的创新点是提出并且细化了5种“假设法”:“反面假设法”“假设古代角色法”“假设A人物和B人物交流法”“假设穿越作品法”“假设访谈法”。
关键词 “假设法” 学科认知情境 语文核心素养
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用“假设转化法”解竞赛题二例
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作者 罗运楷 《小学教学研究》 2002年第3期26-27,共2页
解数学题是要讲究策略的。当我们碰到数学难题采用常规方法不能解答时,不妨把题目中的某个条件进行假设转化,就可变通思路,找到解题的突破点,达到难题巧解的目的。
关键词 “假设转化法” 数学竞赛题 解题方 例题分析
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用“假设化同”法解工程应用题
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作者 孟占英 《教育实践与研究》 2004年第5期62-62,共1页
我在教学工程问题时,发现学生对"中间有停歇"的工程应用题感到发怵,一时找不出解题思路,经常出现误解.我根据这类应用题具有"两人或几人工作时间不统一"的特点,抓住这一规律.运用"假设化同"法,把题中某... 我在教学工程问题时,发现学生对"中间有停歇"的工程应用题感到发怵,一时找不出解题思路,经常出现误解.我根据这类应用题具有"两人或几人工作时间不统一"的特点,抓住这一规律.运用"假设化同"法,把题中某一不同数量假设为相同数量来列式求解.这样,不仅可以化难为易,而且可以拓宽思路,培养发散思维.经过教学实验,收到了良好效果.现举例如下. 展开更多
关键词 “假设化同” 工程问题 应用题 发散思维 小学 数学
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例谈高中物理解题基本思路
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作者 彭友山 《数理化解题研究(高中版)》 2006年第5期34-36,共3页
我们往往遇到一些棘手的物理题,可能一时不知如何解答,笔者在实践中总结了一种“假设法”,妙用“假设法”常常能够轻巧地解决问题.
关键词 物理解题 “假设法” 高中 物理题 解答 妙用
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Solitary Wave Solutions for Generalized Rosenau-KdV Equation 被引量:11
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作者 Amin Esfahani 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第3期396-398,共3页
In this work, we study the generalized Rosenau-KdV equation. We shall use the sech-ansatze method to derive the solitary wave solutions of this equation.
关键词 SOLITONS Ansatze method Rosenau equation KdV equation
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ANALYSIS OF WAVEGUIDE PROBLEMS USING A RELAXED ITERATIVE DOMAIN DECOMPOSITION METHOD COMBINED WITH MULTIFRONTAL ALGORITHM 被引量:2
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作者 Zhu Hanqing Wu Zhengde (Applied Physics Institute, University of Electronic Science and Technology of China, Chengdu 610054)K. M. Luk(Department of Electronic Eng., City University of Hong Kong, Kowloon, Hong Kong SAR, China) 《Journal of Electronics(China)》 2003年第2期110-115,共6页
In this paper, an absorbing Fictitious Boundary Condition (FBC) is presented to generate an iterative Domain Decomposition Method (DDM) for analyzing waveguide problems.The relaxed algorithm is introduced to improve t... In this paper, an absorbing Fictitious Boundary Condition (FBC) is presented to generate an iterative Domain Decomposition Method (DDM) for analyzing waveguide problems.The relaxed algorithm is introduced to improve the iterative convergence. And the matrix equations are solved using the multifrontal algorithm. The resulting CPU time is greatly reduced.Finally, a number of numerical examples are given to illustrate its accuracy and efficiency. 展开更多
关键词 Fictitious boundary condition Domain decomposition method Relaxed algorithm Multifrontal algorithm Waveguide problem
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例谈“假设—否定法”在解答遗传题时的应用
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作者 张忠 张向霞 《学园》 2014年第7期138-138,共1页
本文笔者结合实例,总结了“假设-否定法”在解答生物学科遗传题时的应用。
关键词 “假设-否定法” 解答遗传题 应用
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Perceptions on the Effects of Auditor-Client Relationship upon Audit Quality and Auditor Independence: Evidence from Bahrain
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作者 Hussein Khasharmeh Abdulqawi A. Hezabr 《Journal of Modern Accounting and Auditing》 2016年第10期495-508,共14页
The study aims to focus upon the association between the auditors and companies by indicating how this association affects the quality of audit and auditor independence in a developing country (the case of Bahrain).... The study aims to focus upon the association between the auditors and companies by indicating how this association affects the quality of audit and auditor independence in a developing country (the case of Bahrain). To achieve these objectives, a questionnaire was developed and distributed to respondents from audit firms in Bahrain. Descriptive statistics were used to analyse the influence of auditor-client association upon quality of audit and auditor independence and how audit quality and auditor independence are improved was also explored in the study. The results show that all the questions (1-8) in the questionnaire impair both audit quality and auditor independence with the means ranging from 3.6000 to 4.0364 with an average mean of 3.7212. According to the measurement scale, any item with a mean of 3.50 or more is acceptable, and since all the influences are above 3.50, they are all acceptable. Regarding how auditor-client relationship (or long tenured auditor) would improve both quality of audit and auditor independence, the results show that all the questions (9-17) would improve both audit quality and auditor independence with the means ranging from 3.6364 to 4.0727 with an average of 3.8646, which are acceptable. These results confirm statistically that there is a significant relationship between the auditor long-term tenure and audit quality and auditor independence, so the null hypothesis (H0) is rejected and the alternative hypothesis is accepted. Simple regression analysis is employed to test the hypothesis of the study and its significance. The results show that (H0) hypothesis is not significant. Therefore, the alternative hypothesis (H1) is significant at p 〈 0.005, which means that there are differences in viewpoints among respondents and the p-value obtained is 0.044 which is less than the significant value of p 〈 0.05. These results confirm the hypothesis that a significant relationship exists between the auditor long-term tenure and quality of audit and auditor independence. 展开更多
关键词 audit tenure audit quality partner tenure Bahrain Central Bank of Bahrain (CBB) auditor-clientrelationship Gulf Cooperation Council (GCC)
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Theoretical generalization of Markov chain random field from potential function perspective 被引量:2
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作者 黄翔 王志忠 郭建华 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第1期189-200,共12页
The inner relationship between Markov random field(MRF) and Markov chain random field(MCRF) is discussed. MCRF is a special MRF for dealing with high-order interactions of sparse data. It consists of a single spatial ... The inner relationship between Markov random field(MRF) and Markov chain random field(MCRF) is discussed. MCRF is a special MRF for dealing with high-order interactions of sparse data. It consists of a single spatial Markov chain(SMC) that can move in the whole space. Generally, the theoretical backbone of MCRF is conditional independence assumption, which is a way around the problem of knowing joint probabilities of multi-points. This so-called Naive Bayes assumption should not be taken lightly and should be checked whenever possible because it is mathematically difficult to prove. Rather than trap in this independence proving, an appropriate potential function in MRF theory is chosen instead. The MCRF formulas are well deduced and the joint probability of MRF is presented by localization approach, so that the complicated parameter estimation algorithm and iteration process can be avoided. The MCRF model is then applied to the lithofacies identification of a region and compared with triplex Markov chain(TMC) simulation. Analyses show that the MCRF model will not cause underestimation problem and can better reflect the geological sedimentation process. 展开更多
关键词 localization approach Markov model potential fimction reservoir simulation transiogram fitting
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VIRTUAL SYSTEM METHOD FOR SYSTEM TREE
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作者 ZHENG ZHONGGUO (Department of Probability and Statistics, Beijing University) Be1Jing 100871, China.) 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 1995年第4期509-518,共10页
A machine, or other type of 'system' , can often be divided into several subsystems (components)and these subsystems again can be divided into sevreral subsystems (second generation). This process forms a sy... A machine, or other type of 'system' , can often be divided into several subsystems (components)and these subsystems again can be divided into sevreral subsystems (second generation). This process forms a system tree. To assess the reliability of the machine based on data from the trials of components of the machine, virtual system method is employed. It is proved in the paper that the lower confident limit of the reliability of the machine set by the virtual system method is level consistent and asymptotically optimal while the one set by Lindstrom-Maddens method is not. 展开更多
关键词 Lower confidence limit RELIABILITY Virtual system method System tree
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Statistical Diagnosis and Gross Error Test for Semiparametric Linear Model 被引量:1
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作者 DING Shijun ZHANG Songlin JIANG Weiping WANG Shouchun 《Geo-Spatial Information Science》 2009年第4期296-302,共7页
This paper systematically studies the statistical diagnosis and hypothesis testing for the semiparametric linear regression model according to the theories and methods of the statistical diagnosis and hypothesis testi... This paper systematically studies the statistical diagnosis and hypothesis testing for the semiparametric linear regression model according to the theories and methods of the statistical diagnosis and hypothesis testing for parametric regression model.Several diagnostic measures and the methods for gross error testing are derived.Especially,the global and local influence analysis of the gross error on the parameter X and the nonparameter s are discussed in detail;at the same time,the paper proves that the data point deletion model is equivalent to the mean shift model for the semiparametric regression model.Finally,with one simulative computing example,some helpful conclusions are drawn. 展开更多
关键词 parametric regression semiparametric linear model influencing analysis statistical diagnosis gross error testing
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The convergence rates of Shannon sampling learning algorithms 被引量:2
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作者 SHENG BaoHuai 《Science China Mathematics》 SCIE 2012年第6期1243-1256,共14页
In the present paper,we provide an error bound for the learning rates of the regularized Shannon sampling learning scheme when the hypothesis space is a reproducing kernel Hilbert space(RKHS) derived by a Mercer kerne... In the present paper,we provide an error bound for the learning rates of the regularized Shannon sampling learning scheme when the hypothesis space is a reproducing kernel Hilbert space(RKHS) derived by a Mercer kernel and a determined net.We show that if the sample is taken according to the determined set,then,the sample error can be bounded by the Mercer matrix with respect to the samples and the determined net.The regularization error may be bounded by the approximation order of the reproducing kernel Hilbert space interpolation operator.The paper is an investigation on a remark provided by Smale and Zhou. 展开更多
关键词 function reconstruction reproducing kernel Hilbert spaces Shannon sampling learning algorithm learning theory sample error regularization error
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Singular 1-soliton and Periodic Solutions to the Nonlinear Fisher-Type Equation with Time-Dependent Coefficients
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作者 Ozkan Guner Ahmet Bekir 《Communications in Theoretical Physics》 SCIE CAS CSCD 2016年第4期405-409,共5页
In this article,we establish exact solutions for the variable-coefficient Fisher-type equation.The solutions are obtained by the modified sine-cosine method and ansatz method.The soliton and periodic solutions and top... In this article,we establish exact solutions for the variable-coefficient Fisher-type equation.The solutions are obtained by the modified sine-cosine method and ansatz method.The soliton and periodic solutions and topological as well as the singular 1-soliton solution are obtained with the aid of the ansatz method.These solutions are important for the explanation of some practical physical problems.The obtained results show that these methods provide a powerful mathematical tool for solving nonlinear equations with variable coefficients. 展开更多
关键词 modified sine-cosine method ansatz method the variable-coefficient Fisher-type equation
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A review of 20 years of naive tests of significance for high-dimensional mean vectors and covariance matrices 被引量:1
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作者 HU Jiang BAI ZhiDong 《Science China Mathematics》 SCIE CSCD 2016年第12期2281-2300,共20页
We introduce the so-called naive tests and give a brief review of the new developments. Naive testing methods are easy to understand and perform robustly, especially when the dimension is large. We focus mainly on rev... We introduce the so-called naive tests and give a brief review of the new developments. Naive testing methods are easy to understand and perform robustly, especially when the dimension is large. We focus mainly on reviewing some naive testing methods for the mean vectors and covariance matrices of high-dimensional populations, and we believe that this naive testing approach can be used widely in many other testing problems. 展开更多
关键词 naive testing methods hypothesis testing high-dimensional data multivariate analysis of variance(MANOVA)
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Understanding the evolution of learning by explicitly modeling learning mechanisms 被引量:1
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作者 Michal ARBILLY 《Current Zoology》 SCIE CAS CSCD 2015年第2期341-349,共9页
Models of the evolution of learning often assume that learning leads to the best solution to any task, and disregard the details of the learning and decision-making process along with its potential pitfalls. These mod... Models of the evolution of learning often assume that learning leads to the best solution to any task, and disregard the details of the learning and decision-making process along with its potential pitfalls. These models therefore do not explain in- stances in the animal behavior literature in which learning leads to maladaptive behaviors. In recent years a growing number of theoretical studies use explicit models of learning mechanisms, offering a fresh perspective on the issue by revealing the dynam- ics of information acquisition and biases arising from it. These models have pointed out possible learning rules and their adaptive value, and shown that the value of learning may crucially depend on such factors as the layout of the physical environment to be learned, the structure of the payoffs offered by different alternatives, the risk of failure, characteristics of the learner and social interactions. This review considers the merits of explicit modeling in studying the evolution of learning, describes the kinds of results that can only be obtained from this modeling approach, and outlines directions for future research . 展开更多
关键词 Agent-based simulation Learning bias Learning rule Decision rule COGNITION
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SOLITONS AND CONSERVATION LAWS IN NEUROSCIENCES
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作者 AN JAN BISWAS ABDUL H. KARA +2 位作者 MICHELLE SAVESCU ASHFAQUE H. BOKHARI F. D. ZAMAN 《International Journal of Biomathematics》 2013年第3期101-107,共7页
This paper obtains the 1-soliton solution by the ansatz method for the proposed model that governs the propagation of solitons through the neurons. This model is an improved one that describes the solitons in neurosci... This paper obtains the 1-soliton solution by the ansatz method for the proposed model that governs the propagation of solitons through the neurons. This model is an improved one that describes the solitons in neurosciences more accurately. The ansatz method is applied to obtain the 1-soliton solution to the model. The Lie symmetry analysis is subsequently applied to obtain the conservation laws for the model. 展开更多
关键词 SOLITONS INTEGRABILITY conservation laws neuroscience.
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