电大离散数学(本)7月试题（小抄参考）

1、试卷代号：5-5 座位号 中央广播电视大学 学年度第 学期期末考试计算机科学与技术专业 级第二学期离散数学试题2009年 7月题号一二三四五六总分得分一、单项选择题（每小题3分，本题共15分）1若集合a=1，2，1，2，则下列表述正确的是( ) a2a b1ac1a d2 a2已知一棵无向树t中有8个顶点，4度、3度、2度的分支点各一个，t的树叶数为( )a6 b4 c3 d53设无向图g的邻接矩阵为,则g的边数为( )a1 b7 c6 d144设集合a=a，则a的幂集为( )aa ba，ac，a d，a5下列公式中 ( )为永真式aab ab bab (ab) cab ab dab (ab)

2、二、填空题（每小题3分，本题共15分）6命题公式的真值是 7若无向树t有5个结点，则t的边数为 8设正则m叉树的树叶数为t，分支数为i，则(m-1)i= 9设集合a=1，2上的关系r,，则在r中仅需加一个元素 ，就可使新得到的关系为对称的10(x)(a(x)b(x，z)c(y)中的自由变元有 三、逻辑公式翻译（每小题6分，本题共12分） 11将语句“今天上课”翻译成命题公式12将语句“他去操场锻炼，仅当他有时间”翻译成命题公式 四、判断说明题（每小题7分，本题共14分）判断下列各题正误，并说明理由13设集合a=1，2，b=3，4，从a到b的关系为f=，则f是a到b的函数14设g是一个有4个结点

3、10条边的连通图，则g为平面图 五计算题（每小题12分，本题共36分） 15试求出（pq）（rq）的析取范式16设a=1, 1, 2，b= 1, 2，试计算（1）ab （2）ab （3）a -（ab）17图g=，其中v= a, b, c, d ，e= (a, b), (a, c) , (a, d), (b, c), (b, d), (c, d)，对应边的权值依次为1、2、3、1、4及5，试（1）画出g的图形； （2）写出g的邻接矩阵；（3）求出g权最小的生成树及其权值六、证明题（本题共8分）18试证明：若r与s是集合a上的自反关系，则rs也是集合a上的自反关系if we dont do tha

4、t it will go on and go on. we have to stop it; we need the courage to do it.his comments came hours after fifa vice-president jeffrey webb - also in london for the fas celebrations - said he wanted to meet ivory coast international toure to discuss his complaint.cska general director roman babaev sa

5、ys the matter has been exaggerated by the ivorian and the british media.blatter, 77, said: it has been decided by the fifa congress that it is a nonsense for racism to be dealt with with fines. you can always find money from somebody to pay them.it is a nonsense to have matches played without specta

6、tors because it is against the spirit of football and against the visiting team. it is all nonsense.we can do something better to fight racism and discrimination.this is one of the villains we have today in our game. but it is only with harsh sanctions that racism and discrimination can be washed ou

7、t of football.the (lack of) air up there watch mcayman islands-based webb, the head of fifas anti-racism taskforce, is in london for the football associations 150th anniversary celebrations and will attend citys premier league match at chelsea on sunday.i am going to be at the match tomorrow and i h

8、ave asked to meet yaya toure, he told bbc sport.for me its about how he felt and i would like to speak to him first to find out what his experience was.uefa hasopened disciplinary proceedings against cskafor the racist behaviour of their fans duringcitys 2-1 win.michel platini, president of european

9、 footballs governing body, has also ordered an immediate investigation into the referees actions.cska said they were surprised and disappointed by toures complaint. in a statement the russian side added: we found no racist insults from fans of cska.baumgartner the disappointing news: mission aborted

10、.the supersonic descent could happen as early as sunda.the weather plays an important role in this mission. starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humidity and limited cloud cover. the balloon, with capsule attached, will move throug

11、h the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. it will climb higher than the tip of mount everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. as

12、he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence.the balloon will slowly drift to the edge of space at 120,000 feet ( then, i would assume, he will slowly step out onto something resembling an olympic diving platform.below, the earth becomes the concrete bottom

13、of a swimming pool that he wants to land on, but not too hard. still, hell be traveling fast, so despite the distance, it will not be like diving into the deep end of a pool. it will be like he is diving into the shallow end.skydiver preps for the big jumpwhen he jumps, he is expected to reach the s

14、peed of sound - 690 mph (1,110 kph) - in less than 40 seconds. like hitting the top of the water, he will begin to slow as he approaches the more dense air closer to earth. but this will not be enough to stop him completely.if he goes too fast or spins out of control, he has a stabilization parachut

15、e that can be deployed to slow him down. his team hopes its not needed. instead, he plans to deploy his 270-square-foot (25-square-meter) main chute at an altitude of around 5,000 feet (1,524 meters).in order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). he will have a reserve parachute that will open automatically if he loses consciou