目标函数:
maxZ=90x1+160x2+400x3+100x4
约束条件:
2x1+8x2+4x3+2x4<=41000
5x1+4x2+8x3+5x4<=43000
7x1+8x2+3x3+5x4<=52500
1500<=x1<=2500
2000<=x2<=6000
X3=2000
1000<=x4<=1500
xi>=0 i=1,2,3,4
正解为: x1=1500 x2=3470 x3=2000 x4=1120
考试用的,请给出详解步骤。谢谢。纯数学问题,和程序无关只要解题步骤。谢谢大家。
把x3=3000代入得:
2x1 + 8x2 + 2x4 <= 29000 (1)
5x1 + 4x2 + 5x4 <= 27000 (2)
7x1 + 8x2 + 5x4 <= 45500 (3)Step2:
由(1)+(2)-(3)得关于x2 x4的不等式。
(1)×5-(2)×2得到关于 x2 x4的不等式
……
联合已知条件求解
用x3=3000先消灭一个未知数
根据前三个约束条件向其中一个转化
1500<=x1<=2500
2000<=x2<=6000
1000<=x4<=1500
把他们变成只含有maxZ的式子,求解
3125<=x2<=3500LZ觉得有价值么?
约束条件:
2x1+8x2+4x3+2x4<=41000
5x1+4x2+8x3+5x4<=43000
7x1+8x2+3x3+5x4<=52500
1500<=x1<=2500
2000<=x2<=6000
X3=2000
1000<=x4<=1500
xi>=0 i=1,2,3,4解:先将其化成标准形式有
maxZ=90x1+160x2+400x3+100x4+0x5+0x6+0x72x1+8x2+4x3+2x4+x5 = 41000
5x1+4x2+8x3+5x4+x6 = 43000
7x1+8x2+3x3+5x4+x7=52500
1500<=x1<=2500
2000<=x2<=6000
X3=2000
1000<=x4<=1500
xi>=0 i=1,2,3,4,5,6,7构成单位矩阵,正在上班,回头再接着写