The expectation or expected value of a random variable is a single number that tells you a lot about the behavior of the variable. Roughly, the expectation is the average value, where each value is weighted according to the probability that it comes up. Formally, the expected value of a random variable r defined on a sample space s is: (B)=∑R()Pr(o) To appreciate its signficance, suppose S is the set of students in a class, and we select a student uniformly at random. Let r be the selected student's exam score. Then

汽车制动效能,是指汽车迅速降低车速直至 停车的能力。汽车制动效能的评价指标是制动距 离S(单位m)和制动减速度(单位m/s2)。 1.制动距离 制动距离S,是指汽车以给定的初速u,从踩 到制动踏板至汽车停住所行驶的距离。制动距离 与踏板力(或者制动系管路压力)以及地面的附 着情况有关,也与制动器的热工况有关。 制动减速度是地面制动力的反映,而与地面 制动力与制动器制动力有关

Problem Set 3 Prof. Gene Chang (For Ph. D students, due on Dec. 28th in the class, or TA's office. For M.A. students, due on Dec. 26th, in the class or TA's office. Late turn-in may result in a penalty in the grade) 1. Kland is a Robinson Crusoe type economy. Robinson, as the consumer and the owner of the firm, has the utility function U(x,) =aIn x+ BInI, where is leisure. Robinson's endowment

Chapter 10 Topics Built-In Simple Types s Integral and Floating Point Data Types s Using Combined Assignment Operators s Prefix and Postfix Forms of Increment and Decrement Operators Additional C++ Operator

Chapter2函数 δ1函数概念 Example S=VI t≥0 s=-at t≥0 12 0≤t≤ 2h S=-8 Vg Definition1.设给定实数集合X,若存在一对应法则f,x∈X,3唯一的实数 y∈R与之对应。则称f是定义在X上的函数,记为:

string is composed ofn(20) characters in an orderly sequence recorded as s:“c1C2C3…Cn” S is string name c123n is value is a character n is string length Such as,S=“ TSinghua University

Teaching madel Target language input Engagement Model of classroom Learner's active seard Implementation Learner's comprehensive output Negative input from teacher

A clotheshorse讲究穿戴的人 one' s brain child某人的主意,某人想出来的 Princess Diana was a real clotheshorse. It's hard to imagine how much 等同于 one's original idea she had spent on clothes

profit maximization Content: Some definition Isoprofit curve Demand function and it's properties supply function and it's properties Profit function and it's properties

钢管订购和运输优化模型 要铺设一条A1→A2→…→A13的输送天然气的主管道,如图一所示(见反 面)。经筛选后可以生产这种主管道钢管的钢厂有S1,S2,S图中粗线表示铁 路,单细线表示公路,双细线表示要铺设的管道(假设沿管道或者原来有公路,或 者建有施工公路),圆圈表示火车站,每段铁路、公路和管道旁的阿拉伯数字表示 里程(单位km) 为方便计,1km主管道钢管称为1单位钢管