运筹学习题答案(第一章)
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第一章 线性规划1、由图可得:最优解为2、用图解法求解线性规划: Min z=2x 1+x 2⎪⎪⎩⎪⎪⎨⎧≥≤≤≥+≤+-01058244212121x x x x x x解:由图可得:最优解x=1.6,y=6.4Max z=5x 1+6x 2⎪⎩⎪⎨⎧≥≤+-≥-0,23222212121x x x x x x解:由图可得:最优解Max z=5x 1+6x 2, Max z= +∞Maxz = 2x 1 +x 2⎪⎪⎩⎪⎪⎨⎧≥≤+≤+≤0,5242261552121211x x x x x x x由图可得:最大值⎪⎩⎪⎨⎧==+35121x x x , 所以⎪⎩⎪⎨⎧==2321x xmax Z = 8.1212125.max 23284164120,1,2maxZ .jZ x x x x x x x j =+⎧+≤⎪≤⎪⎨≤⎪⎪≥=⎩如图所示,在(4,2)这一点达到最大值为26将线性规划模型化成标准形式:Min z=x 1-2x 2+3x 3⎪⎪⎩⎪⎪⎨⎧≥≥-=++-≥+-≤++无约束321321321321,0,052327x x x x x x x x x x x x解:令Z ’=-Z,引进松弛变量x 4≥0,引入剩余变量x 5≥0,并令x 3=x 3’-x 3’’,其中x 3’≥0,x 3’’≥0Max z ’=-x 1+2x 2-3x 3’+3x 3’’⎪⎪⎩⎪⎪⎨⎧≥≥≥≥≥≥-=++-=--+-=+-++0,0,0'',0',0,05232'''7'''5433213215332143321x x x x x x x x x x x x x x x x x x x7将线性规划模型化为标准形式Min Z =x 1+2x 2+3x 3⎪⎪⎩⎪⎪⎨⎧≥≤-=--≥++-≤++无约束,321321321321,00632442392-x x x x x x x x x x x x解:令Z ’ = -z ,引进松弛变量x 4≥0,引进剩余变量x 5≥0,得到一下等价的标准形式。
第一章 线性规划1、由图可得:最优解为2、用图解法求解线性规划: Min z=2x 1+x 2⎪⎪⎩⎪⎪⎨⎧≥≤≤≥+≤+-01058244212121x x x x x x解:由图可得:最优解x=1.6,y=6.4Max z=5x 1+6x 2⎪⎩⎪⎨⎧≥≤+-≥-0,23222212121x x x x x x解:由图可得:最优解Max z=5x 1+6x 2, Max z= +∞Maxz = 2x 1 +x 2⎪⎪⎩⎪⎪⎨⎧≥≤+≤+≤0,5242261552121211x x x x x x x由图可得:最大值⎪⎩⎪⎨⎧==+35121x x x , 所以⎪⎩⎪⎨⎧==2321x xmax Z = 8.1212125.max 23284164120,1,2maxZ .jZ x x x x x x x j =+⎧+≤⎪≤⎪⎨≤⎪⎪≥=⎩如图所示,在(4,2)这一点达到最大值为26将线性规划模型化成标准形式:Min z=x 1-2x 2+3x 3⎪⎪⎩⎪⎪⎨⎧≥≥-=++-≥+-≤++无约束321321321321,0,052327x x x x x x x x x x x x解:令Z ’=-Z,引进松弛变量x 4≥0,引入剩余变量x 5≥0,并令x 3=x 3’-x 3’’,其中x 3’≥0,x 3’’≥0Max z ’=-x 1+2x 2-3x 3’+3x 3’’⎪⎪⎩⎪⎪⎨⎧≥≥≥≥≥≥-=++-=--+-=+-++0,0,0'',0',0,05232'''7'''5433213215332143321x x x x x x x x x x x x x x x x x x x7将线性规划模型化为标准形式Min Z =x 1+2x 2+3x 3⎪⎪⎩⎪⎪⎨⎧≥≤-=--≥++-≤++无约束,321321321321,00632442392-x x x x x x x x x x x x解:令Z ’ = -z ,引进松弛变量x 4≥0,引进剩余变量x 5≥0,得到一下等价的标准形式。
第一章 线性规划及单纯形法(作业)1.4 分别用图解法和单纯型法求解下列线性规划问题,并对照指出单纯形表中的各基可行解对应图解法中可行域的哪一顶点。
(1)Max z=2x 1+x 2St.⎪⎩⎪⎨⎧≥≤+≤+0,24261553212121x x x x x x 解:①图解法:由作图知,目标函数等值线越往右上移动,目标函数越大,故c 点为对应的最优解,最优解为直线⎩⎨⎧=+=+242615532121x x x x 的交点,解之得X=(15/4,3/4)T 。
Max z =33/4. ② 单纯形法:将上述问题化成标准形式有: Max z=2x 1+x 2+0x 3+0x 4St. ⎪⎩⎪⎨⎧≥≤++≤++0,,,242615535421421321x x x x x x x x x x其约束条件系数矩阵增广矩阵为:P 1 P 2 P 3 P 4⎥⎦⎤⎢⎣⎡241026150153 P 3,P 4为单位矩阵,构成一个基,对应变量向,x 3,x 4为基变量,令非基变量x 1,x 2为零,找到T 优解,代入目标函数得Max z=33/4.1.7 分别用单纯形法中的大M 法和两阶段法求解下列线性规划问题,并指出属哪一类。
(3)Min z=4x 1+x 2⎪⎪⎩⎪⎪⎨⎧=≥=++=-+=+)4,3,2,1(0426343342132121j xj x x x x x x x x 解:这种情况化为标准形式: Max z '=-4x 1-x 2⎪⎪⎩⎪⎪⎨⎧=≥=++=-+=+)4,3,2,1(0426343342132121j xj x x x x x x x x 添加人工变量y1,y2Max z '=-4x 1-x 2+0x 3+0x 4-My 1-My 2⎪⎪⎩⎪⎪⎨⎧≥=≥=++=+-+=++0,).4,3,2,1(04263433214112321121y y j xj x x x y x x x y x x(2) 两阶段法: Min ω=y 1+y 2St.⎪⎪⎩⎪⎪⎨⎧≥=≥=++=+-+=++0,).4,3,2,1(04263433214112321121y y j xj x x x y x x x y x x第二阶段,将表中y 1,y 2去掉,目标函数回归到Max z '=-4x 1-x 2+0x 3+0x 4第二章 线性规划的对偶理论与灵敏度分析(作业)2.7给出线性规划问题:Max z=2x 1+4x 2+x 3+x 4⎪⎪⎪⎩⎪⎪⎪⎨⎧=≥≤++≤++≤+≤++)4,3,2,1(096628332143221421j x x x x x x x x x x x x j要求:(1)写出其对偶问题;(2)已知原问题最优解为X *=(2,2,4,0),试根据对偶理论,直接求出对偶问题的最优解。
第1章训练题一.基本技能训练1.用图解法求解下列线性规划问题(1)⎪⎪⎩⎪⎪⎨⎧≥≤≥+≤++=0,41501053max 212212121x x x x x x x x x z (2)⎪⎩⎪⎨⎧≥≥+≥++=0,23364min 21212121x x x x x x x x z (3)⎪⎩⎪⎨⎧≥≤+--≥-+=0,25.0122max 21212121x x x x x x x x z (4)⎪⎩⎪⎨⎧≥-≤-≥-+=0,33022max 21212121x x x x x x x x z1.用图解法求解下列线性规划问题(1). 唯一最优解14,)4,2(**==z X T; (2). 唯一最优解9,)21,23(**==z X T ; (3). 无界解; (4). 无可行解;2.用单纯形法求解下列线性规划问题(1)⎪⎪⎩⎪⎪⎨⎧≥≤+≤≤+=0,1823122453max 21212121x x x x x x x x z (2) ⎪⎪⎩⎪⎪⎨⎧≥≤-+≤+-≤+++-=0,,201026032max 321321321321321x x x x x x x x x x x x x x x z (3)⎪⎪⎩⎪⎪⎨⎧≥≤++-≤++-≤--++++=0,,,1032425823320446581026max 43214321432143214321x x x x x x x x x x x x x x x x x x x x z (4)⎪⎪⎩⎪⎪⎨⎧≥≥≥≤++≤+-≤++-++=3,2,11722044132246max 321321321321321x x x x x x x x x x x x x x x z (5)⎪⎪⎪⎩⎪⎪⎪⎨⎧≥≤+≤+≤++≤++++=0,,1234166482212322532max 3213231321321321x x x x x x x x x x x x x x x x z (6)⎪⎪⎩⎪⎪⎨⎧≥≤+++≤+++≤++++++=0,,,9005387800584548024821004016090max 43214321432143214321x x x x x x x x x x x x x x x x x x x x z(7)⎪⎪⎪⎩⎪⎪⎪⎨⎧≥≤≤≥+≥+=0,4.126.18.018001000min 212121121x x x x x x x x x z (8)⎪⎩⎪⎨⎧≥≥+≥++++=0,,62382432min 32121321321x x x x x x x x x x x z (9)⎪⎪⎩⎪⎪⎨⎧≥≥++≤++-≤++++=0,,52151565935121510max 321321321321321x x x x x x x x x x x x x x x z (10)⎪⎪⎩⎪⎪⎨⎧≥=+++=++=++-++=0,,,1022052153232max 432143213213214321x x x x x x x x x x x x x x x x x x z (11)⎪⎪⎩⎪⎪⎨⎧≥≥-≥+-≥+++-=0,,0222622max 3213231321321x x x x x x x x x x x x x z (12) ⎪⎪⎩⎪⎪⎨⎧≥=++≤++≤++++=无约束,3213213213213210,101632182635max x x x x x x x x x x x x x x x z (13)⎪⎩⎪⎨⎧≥≤+≤+-=0,5623min 21212121x x x x x x x x z (14)⎪⎩⎪⎨⎧≥≤-≤++=0,1262385max 21212121x x x x x x x x z(15)⎪⎩⎪⎨⎧≥≤++≤++-+-=0,,1043223232min 321321321321x x x x x x x x x x x x z (16)⎪⎪⎩⎪⎪⎨⎧≥≤+-≤-+≤+++-=0,,9362122max 32121321321321x x x x x x x x x x x x x x z(17)⎪⎪⎩⎪⎪⎨⎧≥≤++≤+-+≤-++-+--=0,,,41232642532min 4321431432143214321x x x x x x x x x x x x x x x x x x x z (18)⎪⎪⎪⎩⎪⎪⎪⎨⎧≤≤-≤+-≥+--≥---=0,16482623323min 212121212121x x x x x x x x x x x x z (19)⎪⎪⎩⎪⎪⎨⎧≥=++≤+≤+++=0,,132173132343max 3213213231321x x x x x x x x x x x x x z (20)⎪⎪⎩⎪⎪⎨⎧≥≤++-≥+-≥++-+=0,,452233min 32132121321321x x x x x x x x x x x x x x z(21)⎪⎪⎩⎪⎪⎨⎧≥=++≥++≤++++=0,,1 29002500350038007080 6560 670075008400min 321321321321321x x x x x x x x x x x x x x x z(22)⎪⎩⎪⎨⎧≥-=-+-=--++++=0,,,376284327432max 4321432143214321x x x x x x x x x x x x x x x x z(22). 唯一最优解5117,)57,0,0,534(**==z X T ; (23)⎪⎩⎪⎨⎧≥=+++=+++-+-=0,,,32274326325min 4321432143214321x x x x x x x x x x x x x x x x z(23). 唯一最优解3,)1,1,0,0(**-==z X T;(24)⎪⎩⎪⎨⎧≥≥+-=++-+=0,,10527532max 321321321321x x x x x x x x x x x x z(24). 唯一最优解7102,)0,74,745(**==z X T ;(25)⎪⎩⎪⎨⎧≥≥+≥++=0,7742min 21212121x x x x x x x x z (26) ⎪⎪⎩⎪⎪⎨⎧≥≥+++≥-+-≥++++++=0,,,1562522730542423min 43214321432143214321x x x x x x x x x x x x x x x x x x x x z(25). 1331,)1310,1321(**==z X T ; (26). 9,)0,0,0,3(**==z X T(27)⎪⎩⎪⎨⎧≥≤+++≤+++++=0,,,1222282652max 432143214314321x x x x x x x x x x x x x x x z (27). 唯一最优解44,)4,4,0,0(**==z X T;(28)⎪⎪⎩⎪⎪⎨⎧≥≤++≤++≤++0,,4201013240085103001028321321321321321x x x x x x x x x x x x(28). 唯一最优解152029,)322,5116,15338(**==z X T ; (29)⎪⎩⎪⎨⎧≥≤++≤++++=0,,30222010127max 321321321321x x x x x x x x x x x x z(29). 唯一最优解220,)10,10,0(**==z X T;(30)⎪⎩⎪⎨⎧≥≤++≤++++=0,,30222061615max 321321321321x x x x x x x x x x x x z(30). 唯一最优解240,)0,15,0(**==z X T;(31)⎪⎪⎩⎪⎪⎨⎧≤+≤+--≤-+-+=无正负号限制32121321321321,,63445322max x x x x x x x x x x x x x x z(31). 唯一最优解211,)49,411,49(**=--=z X T ; (32)⎪⎩⎪⎨⎧≥≥++≤++++=0,,824322323max 321321321321x x x x x x x x x x x x z(32). 唯一最优解4,)0,2,0(**==z X T;(33)⎪⎩⎪⎨⎧≥≤≤-+-=++-+-=无正负号限制321321321321,0,06422min x x x x x x x x x x x x z(33). 唯一最优解12,)1,0,5(**-=--=z X T;(34)⎪⎩⎪⎨⎧≥=-=++0,,423232121321x x x x x x x x(34). 唯一最优解5,)1,0,2(**==z X T;(35)⎪⎩⎪⎨⎧≥-≤+≥+-+=0,2122min 21212121x x x x x x x x z(35). 无可行解;(36)⎪⎩⎪⎨⎧≤≤≤≤≤≤≤++≤++++=30,52,40233421422253max 321321321321x x x x x x x x x x x x z(36). 唯一最优解4123,)0,415,4(**==z X T ; (37)⎪⎩⎪⎨⎧≥≤--=++++=0,,40653025325max 321321321321x x x x x x x x x x x x z(37). 唯一最优解150,)0,0,30(**==z X T ;(38)⎪⎩⎪⎨⎧≥≤+++≤++++++=0,,,2023220322432max 4321432143214321x x x x x x x x x x x x x x x x z(38). 唯一最优解28,)4,4,0,0(**==z X T;(39)⎪⎩⎪⎨⎧≥≥++≥++++=0,,10536423425min 321321321321x x x x x x x x x x x x z(39). 唯一最优解3/22,)0,2,3/2(**==z X T;(40)⎪⎪⎩⎪⎪⎨⎧≥≥-≤+=--+=0,,28242max 321323232132x x x x x x x x x x x x z (40). 唯一最优解8,)2,4,10(**==z X T; 2.用单纯形法求解线性规划问题 (1). 唯一最优解36,)6,2(**==z X T; (2). 唯一最优解25,)0,5,15(**==z X T; (3). 无界解;(4). 有无穷多最优解,其一47,)7,25.2,5.5(**==z X T; (5). 唯一最优解5.16,)2,5.1,1(**==z X T; (6). 唯一最优解18000,)140,0,25,0(**==z X T; (7). 唯一最优解1640,)8.0,1(**==z X T;(8). 有无穷多最优解,其一7,)8.1,8.0(**==z X T; (9). 无可行解;(10). 唯一最优解15,)0,5.2,5.2,5.2(**==z X T; (11). 无界解;(12). 唯一最优解46,)4,0,14(**=-=z X T; (13). 唯一最优解9,)3,0(**-==z X T; (14). 唯一最优解24,)3,0(**==z X T; (15). 唯一最优解5.5,)0,3,5.0(**-==z X T; (16). 有无穷多最优解,其一12,)6,0,6(**==z X T; (17). 唯一最优解368,)4,0,38,0(**-==z X T ; (18). 无界解;(19). 唯一最优解41,)2,11,0(**==z X T; (20). 无可行解;(21). 有无穷多最优解,其一321700,)31,32,0(**==z X T 。
运筹学作业(清华版第一章习题)答案运筹学作业(第一章习题)答案1.1用图解法求解下列线性规划问题,并指出问题具有唯一最优解、无穷多最优解、无界解还是无可行解。
(2)12121212m ax 322..34120,0z x x x x s t x x x x =++≤??+≥??≥≥?解:先画出问题的可行区域:如右图所示,两条边界直线所围成的区域没有公共部分,即可行区域是空的。
故该问题无可行解。
1.2将下述线性规划问题化成标准形式:(1)12341234123412341234m in 3425422214..232,,0,z x x x x x x x x x x x x s t x x x x x x x x =-+-+-+-=-??+-+≤??-++-≥??≥?无约束, 解:由于4x 无约束,故引进两个新变量,即444x x x '''=-代入原问题,并对方程2和方程3分别引入新变量5x 和6x ,则此问题的标准形式为: 12344123441234451234461234456m ax ()342554222214..232,,,,,,0z x x x x x x x x x x x x x x x x s t x x x x x x x x x x x x x '''-=-+-+'''-+-+=-??'''+-+-+=??'''-++-+-=??'''≥?1.4分别用图解法和单纯型法求解下述线性规划问题,并对照指出单纯表中的各基可行解对应图解法中可行区域的哪一顶点。
(1)12121212m ax 105349....5280,0z x x x x s t s t x x x x =++≤??+≤??≥≥? 解:图解法:先画出可行区域K ,如右图所示,K 即为OABC ,B 点为最优解。