第四章信息与信息化管理 一、单项选择题 1、()属于信息。 A.文字B.图形C.曲线D.图细 2、信息评估的关键在于() A.确认信息质量B.评估信息的收益 C.估计信息获取成本D.进行成本一收益分析 3、系统分析的目的在于() A.确定是否存在一个能被信息系统处理的机会 B.产生一个运行系统 C.考察系统的技术能力 D.确定信息系统的功能要求

Any given arm of the Y network is found by taking the product of the two adjacent arms of the network and dividing by the sum of the network arms

The series combination of voltage sources: Several voltage sources in series may be replaced by an equivalent voltage source having a voltage equal to the algebraic sum of the individual sources

A point at which two or more elements have common connection is called node(节点). Suppose that we start at one node in a network and move through a simple element to the node at the other..., if no node was encountered more than once, then the set of nodes and elements that we have passed hrough is defined as path(路径)

Ohm's law states that voltage across many types of conducting materials is directly proportional to the current flowing through the material. U= Ri or R= i R--resis tance()( linear resistor) The resistor is a passive element that cannot deliver power or store energy

一、单项选择题(每小题1分,共10分) 1、生态学按其性质一般分为:() A理论生态学B草原生态学C环境生态学D理论生态学与应用生态学

一、单项选择题(每小题1分,共10分) 1生态学按其性质一般分为: A理论生态学B.草原生态学C环境生态学D理论生态学与应用生态学

2.1 SOME NOTATION 1. The Summation Notation X, =X1++...+n can be abbreviated as:Σx,orΣx 2. Properties of the Summation Operator

1.宽度为r、高度为1的矩形脉冲g(7)的傅氏变换是G()=rsnc(/r) os(atp)=cosa cos B msin a sin B ∫et=en(x)

1、水平角测量原理 水平角是指过空间两条相交方向线所作的铅垂面 间所夹的二面角,角值为0°~360°。空间两 直线OA和OB相交于点O,将点A,O,B沿铅垂 方向投影到水平面上,得相应的投影点A′,O′, B′,水平线O′A′和O′B′的夹角B就是过两 方向线所作的铅垂面间的夹角,即水平角