锐角三角函数在计算圆的半径中的应用简

高中阶段数学第一章集合概念比较抽象,由此给学习带来困难,出现许多错误．现举例如下,供同学们学习参考．     

导数小结论 两年压轴题简

由于Aan＋1=Ban＋f（n）〈=〉an＋1=B/Aan＋1/Af（n）〈=〉Can＋f（n）（n∈N＊）,A≠0）.     

运用韦达定理五注意简

在高中数学人教B版必修4课节1．2．2单位圆与三角函数线一节中,课本思考与讨论中出现结论sinx＜x＜tanx,x∈（0,π/2）,这个不等式揭示了锐角x的弧度数与sinx、tanx的关系,本文举例说明该三角不等式在解题中的一些运用．     

增长曲线模型的非参数估计简

In the research it is frequently assumed that the growth curve is a polynomial in time. In practice, researchers mainly use higher-order polynomials to obtain more precise estimates. But this method has many defects, such as the model can be easily affected by outliers and the polynomial hypothesis may be much strong in practice. So in this paper we first proposed nonparametric approach, local polynomial, instead of parametric method for estimation in growth curve model. We give the nonparametric growth curve model, and its nonparametric estimation. Then discuss the large sample character of local polynomial estimate. The ideal theoretical choice of a local bandwidth is also discussed in detail in this paper. Finally, through the simulation study, from the fitting curve and average square error box plot we can clearly see that the performance of nonparametric approach is much better than parametric technique.     

频率分布直方图中的问题及解法简

由倍角公式和同角三角函数间的关系很容易证得sina=2tan α/2/1＋tan^2 α/2,cosα=1-tan^2α/2/1＋tan^2α/2,tanα=2tan α/2/1-tan^2 α/2,这三个公式通常称之为万能公式．     

对一道初赛题的解法探究简

已知关于x的方程｜x—k｜=√2/2k√x在区间[k-1,k＋1]上有两个不相等的实根,则实数k的取值范围是_____．     

对函数单调性的再认识简

我们知道,如果三个向量a,b,c不共面,那么,对空间任一向量P,存在有序实数组{x,y,z},使得p=xa＋yb＋zc．我们把{a,b,c}叫做空间的一个基底,     

On pseudo-umbilical Lagrangian submanifolds in CP3简

In this paper, an estimate of the constant scalar curvature of a compact non- minimal pseudo-umbilical Lagrangian submanifold in CP3 is obtained. As its application, we prove that compact Einstein pseudo-umbilical Lagrangian submanifolds in CP3 must be minimal.