一、对称美的利用 例1.求sin10°sin30°sin50°sin70°的值。 考虑到sinαcosα=1/2sin2α,可用它的对称式(对偶式)助解:令x=sin10°sin30°sin50&
Fractal interpolation has been an important method applied to engineering in recent years. It can not only be used tofit smooth curve and stationary data but al
大家知道,△ABC的内接三角形的周长存在最小值的充要条件是△ABC为锐角三角形,其最小值为4RsinAsinBsinC(R为△ABC的外接圆半径)。那么,四边形的内接四边形的周长存在最小值
提出好的问题并巧妙地予以解决,是推动数学竞赛活动深入发展的内在动力,开展对竞赛命题的研究,已逐渐成为“竞赛数学”的重要组成部分,也是广大教育工作者、各级教练员进行培
非标准的数学题,是近几年来各级数学竞赛中的热门问题.有些非标准数学题,是研究事物的某种状态或性质的,其本身与数量无关.但若能合理地、巧妙地对某些元素赋予确定的特殊值(
This paper concerns the calculation of the wave trough exceedance probabilities in a nonlinear sea.The calculations have been carried out by incorporating a sec
The fluid viscosity is known to have a significant effect on the hydrodynamic characteristics which are linked to the power conversion ability of the wave energ
第一试 一、选择题（每小题6分,共48分） 1.若100/x】1994<sup>1/2</sup>-25】125/（x+2）,则正整数x是（ ）。 （A）4 （B）5 （C）6 （D）7 2.给定数列:4,5,6,7,8,9,13,14,15,25,26,27,…,按照其固有的
In this paper, the hydrodynamic coefficients of a horizontal semi-immersed cylinder in steady current and oscillatory flow combining with constant current are o
In order to increase the performance of horizontal tidal turbines, a multi-objective optimization model was proposed in this study. Firstly, the prediction mode