关于3个Lucas数乘积和的高次恒等变换

研究了3个Lucas数乘积和的变换问题，给出了r次(r＝2s)恒等变换公式及r＝4时的变换．     

浅谈数学计算中的恒等变换

恒等变换为数学中的重要变换之一,常用的恒等变换有二种类型,一是含有有理式运算中的恒等变换,二是含有无理式运算中的恒等变换,经恒等变换后可起到简化运算,化简数学式子,给计算带来极大的好处,有些较难的作图题,经恒等变换后,可大大简化作图的步骤。     

寓于三角恒等变换中的代数证法

三角恒等变换是三角函数中的一个重要组成部分,它是学习自然科学和高等数学的基础。三角恒等变换方法诸多,本文谈寓于三角恒等变换中的代数证法。     

三角恒等变换思路的运用

三角恒等变换一直是高考的热点之一,无论是作为纯化简题还是复合题中的一步,三角恒等变换一直扮演着重要角色,三角恒等变换的运用也是多种多样.在这里,我用一个简单的小题举例,来分析一下三角恒等变换的具体运用方式求y=tan20°+4sin20°的值.     

注重解题技巧 优化恒等变换——高中数学三角恒等变换解题技巧概述

<正>三角恒等变换是三角函数的应用技巧,同时也是高中数学内容的重要组成部分.三角恒等变换是解决三角函数问题的重要途径,利用公式恒等变形实现三角函数的化简、计算,从而为高效解决数学问题和实际困惑提供科学的依据.一、通过角度拆分,实现函数转换在恒等变换的学习中,角度变换是进行恒等变换的重要突破口,这主要是因为在恒     

如何判断三角形的形状

利用恒等变换判断三角形的形状 判断三角形形状的一个重要策略是恒等变换,即使对于利用了正、余弦定理判断三角形形状的问题,也离不开三角公式的恒等变换,特别是一些倍角公式、和差化积公式、降幂公式、半角公式的熟练应用．     

三角恒等变换常考题型及解析

三角恒等变换是三角函数部分常考的知识点,是求三角函数极值与最值的一个过渡步骤。有时求三角函数周期、对称轴等,需要将三角函数式化成一个角的三角函数形式,其中化简的过程就用到三角恒等变换。有关三角恒等变换的常考题型及解析总结如下。     

三角恒等变换失分点剖析

<正>三角恒等变换是高考考查的重要知识点之一.但在角的合理转化,构造齐次式,均值不等式与三角恒等变换的综合,以及平面四边形中的三角恒等变换问题中,部分考生还显得捉襟见肘,力不从心,这是他们在三角恒等变换中容易出现的失分点,所以掌握好它们就显得十分必要.下面通过归类举例的方法加以具体说明.失分点1角的合理转化     

三角恒等变换技巧

三角恒等变换问题在历年高考和自主招生试题中屡见不鲜。主要考查考生的逻辑推理和运算求解能力．主要是通过三角公式进行等价变换以达到化简、求值、证明的目的．其实三角恒等变换说起来就那么几个公式——虽然多，但是有规律：就那么几个套路一不是正用就逆用；但从实际考试效果看．还是有相当一部分考生不能在短时间内找到解决问题的最佳方案．针对这些问题，本文着重分析各类试题中有关三角恒等变换的问题，主要剖析命题切入点，以及围绕三角恒等变换的解题方法和思路．     

巧用“变角”解三角恒等变换问题

三角恒等变换是高中数学内容的重要组成部分,是三角函数的基础,同时也是高中生应具备的数学能力之一．解决三角恒等变换问题时应根据教材内容,熟悉三角函数,学会灵活适用各种公式中,进而增强其变换意识．变角是解决三角恒等变换的重要方法,巧用“变角”,便于将已知角与未知角相连接起来,进而寻找各个角之间的关系,轻松解题．本文以实例探讨如何应用“变角”来解决三角恒等问题．     

Am I a teacher? How educare givers in Taiwan construct their professional identity during socialisation into public preschools

A new job position, “educare giver,” which was created after kindergartens and preschools in Taiwan were integrated in 2012, has caused several problems such as ambiguity in the role of childcare givers and inequity in the division of labour. Studies have provided a limited scope and have not examined the identities and struggles of educare givers at the individual and organisational levels. This study investigated the effect of contextual factors on the professional identities of educare givers during their socialisation. The researchers adopted a qualitative research design and conducted in-depth interviews with 20 educare givers at public preschools. The findings reveal that educare giver identities are those as teachers, labourers, and teaching and administrative assistants. Contextual factors that affect the construction of their identities at the three stages of their socialisation are information channels, educational background, the recruitment process, titles, the attitudes of stakeholders, and job assignments.     

Intersections of life histories and science identities: the stories of three preservice elementary teachers

Grounded within Connelly and Clandinin’s conceptualization of teachers’ professional identity in terms of ‘stories to live by’ and through a life-history lens, this multiple case study aimed to respond to the following questions: (a) How do three preservice elementary teachers view themselves as future science teachers? (b) How have the participants’ life histories shaped their science identity trajectories? In order to characterize the participants’ formation of science identities over time, various data regarding their life histories in relation to science were collected: science biographies, self-portraits, interviews, reflective journals, lesson plans, and classroom observations. The analysis of the data illustrated how the three participants’ identities have been in formation from the early years of their lives and how various events, experiences, and interactions had shaped their identities through time and across contexts. These findings are discussed alongside implications for theory, specifically, identity and life-history intersections, for teacher preparation, and for research related to explorations of beginning elementary teachers’ identity trajectories.     

后殖民主义视野下的"情人"形象--从《抵挡太平洋的堤坝》到《来自中国北方的情人》

玛格丽特·杜拉斯在1950年出版的<抵挡太平洋的堤坝>、1984年出版的<情人>和1991年出版的<来自中国北方的情人>中都描写了同一段情感故事中的同一个情人.但是,在三部作品中情人却出现了不同的形象和不同的种族身份.本文试图从后殖民主义的角度探讨其形象变化不定背后的种族因素.     

Integrating the ontological,epistemological, and sociocultural aspects: a holistic view of teacher education

The three aspects of teacher change – ontological, epistemological, and sociocultural – are traditionally regarded as independent. Usually only the epistemological aspect is highlighted in formal teacher education. In this paper, I argue that a holistic and interdependent view of these aspects is needed. Thus, this paper aims to explore the process of teacher learning from a holistic perspective. Through deliberative discussions and selection, 13 ‘good’ teachers were interviewed in this study. The findings indicate that there may be a two-stage pattern (the II-VA model) that describes two different sorts of teachers. The first sort refers to those teachers who developed strong identities before beginning their teaching service and who tended to have a clearer educational vision which had a direct impact on their practices and professional development. As for the second sort, the teachers’ identities were vague in their first years of teaching, but their professional identities gradually developed within the referential community with affective and professional functions. These stages imply that we should replace ‘abstract theory’ with ‘subject reflection’ in the center of teacher education. Three kinds of reflection (theory-rationale, identity-integration and vision-accomplishment) are thus identified from a holistic view of teacher change.     

The role of the narrator in narrative inquiry in education: construction and co-construction in two case studies

This paper explores narratives as an effective means of capturing multiple identities of research participants in complex social environments in education research. In doing so, it explores the role of the narrator in two case studies in two modes of narrative inquiry. Both studies present narratives of young people, focusing on multiple identities which are influenced by a variety of cultural and sub-cultural contexts which the participants inhabit to varying degrees. In the first case study, the researcher is the narrator; in the second, it is the research participants. The paper uses the two case studies to discuss three challenging areas in narrative research: participant voice, contextual complexities and researcher positionality and how the researcher responds to these challenges through construction and co-construction of the narratives. The authors share their strategies for addressing these three challenges in relation to the role of the narrator.     

电子商务环境下电子签名与认证之法律思考--兼评<广东省电子交易条例>的相关规定

电子签名与认证是电子商务中确证交易对手身份的重要法律制度。本文首先界定了电子签名的内涵，继而对电子签名的法律效力以及认证机构的地位、职责及法律责任进行了思考，并对《广东省电子交易条例》的相关规定进行了评述。     

Gender,sexuality and schooling: Everyday life in junior secondary schools in Botswana and Ghana

In this paper, the focus is upon daily school practices in Junior Secondary Schools in Ghana and Botswana. The data from 12 ethnographic case studies have been used to explore how the institution of schooling is gendered. The analysis focuses predominantly on the informal practices of the hidden curriculum through a theoretical perspective that highlights these institutional processes as significant to the production of gender/sexual identities. Remarkable similarities in the pervasive and inequitable gender/sexual practices within schools across country contexts are discussed in three key areas: school management and duties, gender space and gender violence. These discussions of everyday school life illustrate the ways in which both normative institutional practices and human agency produce and regulate gender/sexual identities. This micro-level analysis provides important substantive and methodological insights into what goes on inside schools and into the contexts and experiences of schooling that are significant to policy discourses of gender, education and development.     

The emperor has no clothes: examining the impossible relationship between gendered and academic identities in middle school students

Despite the social equity work that still needs to be done in schools and society, many researchers, politicians, and social commentators claim that gender equity work in schools has been accomplished. These people assume that actions in school lead to gender equity outside it. But, there may be two problems with this assumption: 1) achieving equity in academic work may mask still‐inequitable gender work in schools and 2) girls’ and boys’ equal academic achievement does not promise social equality, inside or outside schools. The following study offers evidence from a recent middle school study that reveals how children’s gender identities are naturalized as neutral “student” identities, making the effects of children’s gender identity work invisible. This author argues that schooling at best maintains the inequity of the American gender status quo, and perhaps may work to actually lessen chances for women and men’s equitable life opportunities.     

等价微分恒等式及应用

讨论了四组微分恒等式的等价性,利用它们导出了三个已知微分恒等式和一个新的微分恒等式．