Multiple Choice If one person can perform a task in fewer hours than another, you know the person has in performing the task. a. an absolute advantage. b. a comparative advantage. C. both a comparative advantage and an absolute advantage. rd. neither an absolute nor a comparativ advantage

一、集合 把一些事物汇集到一起组成的一个整体就叫做集合； 常用大写字母A、B、C 等表示集合； 当a是集合A的元素时，就说a 属于A，记作：

7.1 Dictionaries A dictionary is a collection of elements each element has a field called key, and no two elements have the same key value. Operations: Insert(x): insert an element with a specified key value Search(k,x): search an element with a specified key

3.1.2 A general uniqueness theorem The key issue for uniqueness of solutions turns out to be the maximal slope of a=a(a) to guarantee uniqueness on time interval T=[to, t,, it is sufficient to require existence of a constant M such that

幂法的收敛速度主要取决于比值/,若比值越小 则收敛越快;当接近于1时,则收敛很慢这时采用原点平移 法可加快幂法的收敛速度. 设A的特征值为,2,…n,则A-p的特征值为 -p,2-p,…n-p,且A与A-p1的特征向量相同对矩阵A-p

Monopoly While a competitive firm is a price taker, amonopoly firm is a price maker. A firm is considered a monopoly if . . . – it is the sole seller of its product. – its product does not have close substitutes

定义.设a,B是自变量同一变化过程中的无穷小, 若lim=0,则称β是比a高阶的无穷小,记作 B=o(a) 若lim=∞,则称B是比a低阶的无穷小; 若lim=C≠0,则称B是a的同阶无穷小;

第十二章张量积与外代数 12-1多重线性映射 12.1.1线性空间的一组基的对偶基的定义 定义12.1对偶空间 设v是k上n维线性空间,E2,Sn是的一组基,则线性函数 f:V→K(K为数域)被f在此组基下的映射法则决定,即f()f(2)f(n)已给 定。现设V内全体线性函数组成的集合为V,则在V内定义加法与数乘如下: (i)f,,+)(a)= f(a)+g(a); (iif EV', k K, f )(a)= (a). 则V关于上述加法、数乘组成K上的线性空间,称为V的对偶空间,记作o(V,K 定义12.2对偶基 假设同定义12.1,定义V内n个线性函数

The length of a sound is the length of time during which it is held on continuously in a given word or phrase. The principal facts concerning length in English are given in the following rules: 203. Length of vowels 1. English vowels /i:/, /a: / /:/, /u:/, /a: /are longer than the other English vowels in similar context, i.e., when surrounded by the same sounds, and pronounced with the same degree of stress. Thus

现在来证明,-矩阵的标准形是唯一的 定义5设λ-矩阵A(4)的秩为r,对于正整数k,1≤k≤r,A(4)中必有非 零的k级子式.A(4)中全部k级子式的首项系数为1的最大公因式D(4)称为 A(A)的k级行列式因子 由定义可知,对于秩为r的λ-矩阵,行列式因子一共有r个行列式因子的 意义就在于,它在初等变换下是不变的