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聚焦2005年高考数学平面向量试题的“交汇性”
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作者 刘允忠 《中学数学研究》 2005年第8期17-20,共4页
向量是新课程新增内容,具有代数与几何形式的双重身份,它有着极其丰富的实际背景,用向量证明几何中有关平行、共线和垂直的命题,用向量计算角度和距离,用向量表示点的轨迹,以及用向量处理三角恒等变形,证明不等式,求解函数的最... 向量是新课程新增内容,具有代数与几何形式的双重身份,它有着极其丰富的实际背景,用向量证明几何中有关平行、共线和垂直的命题,用向量计算角度和距离,用向量表示点的轨迹,以及用向量处理三角恒等变形,证明不等式,求解函数的最值,较之传统方法更为简捷. 展开更多
关键词 2005年 高考 数学 平面向量试题 “交汇性” 课程改革 试题解析
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有关y=Asin(ωx+φ)+B的试题的“交汇性”
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作者 王勇 《中学生数学(高中版)》 2003年第01s期27-29,共3页
关键词 y=Asin(ωx+φ)+B 试题 “交汇性” 高考 数学 命题 特点
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Copula-Based Risk Management Models for Multivariable RMB Exchange Rate in the Process of RMB Internationalization 被引量:2
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作者 DU Jiangze LAI Kin Keung 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2017年第3期660-679,共20页
This paper investigates the dependence of the exchange rate of onshore Renminbi(RMB)and offshore RMB against US dollar(i.e., CNY and CNH) based on copula models. Eleven different copulas were selected to construct mul... This paper investigates the dependence of the exchange rate of onshore Renminbi(RMB)and offshore RMB against US dollar(i.e., CNY and CNH) based on copula models. Eleven different copulas were selected to construct multivariate distribution and estimate the value-at-risk for RMB exchange rate. Empirical results show that time-invariant Student-t copula is the best model to fit the sample data. The positive upper and lower dependence indicates that CNY and CNH series tend to move in the same direction. Moreover, the dependence between the two exchange rates is asymmetric,which means that traditional models, such as Pearson's correlation, are inappropriate to measure the correlations between these markets. The best fitted model is chosen to estimate the financial risk,which can help business practitioners and policymakers track risk evolution and make good decisions. 展开更多
关键词 Copula modeling RMB exchange rate RMB internationalization value-at-risk.
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LEXICAL RICHNESS IN L2 ACADEMIC WRITING 被引量:2
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作者 汪澜 《Chinese Journal of Applied Linguistics》 2005年第5期18-23,128,共7页
This preliminary study investigates the relationship between lexical richness and communicative effectiveness in placement essays for graduate students whose first language (L1) is Chinese. Lexical richness is measure... This preliminary study investigates the relationship between lexical richness and communicative effectiveness in placement essays for graduate students whose first language (L1) is Chinese. Lexical richness is measured with Nation's web-based vocabulary profiler (Cobb, undated) software, and communicative effectiveness is scored by multiple raters. The structure of the study, lexical data compile review, results analysis, and teaching implications will be discussed. The study indicates that lexical richness needs to be taken into account in scoring the quality of writing. However, further investigation and analysis still need to be developed and discussed on the ongoing study. 展开更多
关键词 lexical richness communicative effectiveness L2 academic writing type/token ratio essay score corpus linguistics
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