最新数学建模第四版第七章课后答案

第七章

第一题

clc

%数据输入

x=[68 68 87 87 106 106 140 140];

y=[9.7981 13.324 9.0078 13.355 9.7918 14.277 9.6563 12.463]; z=[0.0848 0.0897 0.0762 0.0807 0.0696 0.0753 0.0611 0.0651]; %²插值

cx=99;

cy=10.3;

cz=griddata(x,y,z,cx,cy,'cubic')

%做表面图

%meshz(cx,cy,cz)

cz =

0.0724

第二题

x=[129 140 103.5 88 185.5 195 105.5 157.5 107.5 77 81 162 162 117.5];

y=[7.5 141.5 23 147 22.5 137.5 85.5 -6.5 -81 3 56.5 -66.5 84

-33.5];

z=[4 8 6 8 6 8 8 9 9 8 8 9 4 9];

%²插值

cx=75:0.5:200;

cy=-50:0.5:150;

cz=griddata(x,y,z,cx',cy,'cubic')

4.7984 4.7554 4.7129 4.6711 4.6299 4.5893 4.5494 4.5102 4.4718 4.4341

4.8239 4.7808 4.7383 4.6963 4.6550 4.6142 4.5742 4.5348 4.4962 4.4583

4.8492 4.8061 4.7635 4.7214 4.6800 4.6391 4.5990 4.5594 4.5206 4.4825

4.8744 4.8312 4.7885 4.7464 4.7049 4.6639 4.6236 4.5840 4.5450 4.5067

4.8992 4.8560 4.8133 4.7711 4.7295 4.6885 4.6481 4.6084 4.5693 4.5309

4.9237 4.8805 4.8378 4.7956 4.7539

4.7129 4.6724 4.6326 4.5934 4.5549

4.9478 4.9046 4.8619 4.8197 4.7780 4.7369 4.6964 4.6565 4.6172 4.5786

4.9715 4.9283 4.8856 4.8433 4.8016 4.7605 4.7200 4.6800 4.6407 4.6021

4.9946 4.9514 4.9087 4.8665 4.8248

4.7837 4.7431 4.7031 4.6638 4.6251

5.0172 4.9740 4.9313 4.8891 4.8474

4.8063 4.7657 4.7257 4.6864 4.6476

5.0391 4.9960 4.9533 4.9111 4.8694

4.8283 4.7877 4.7477 4.7083 4.6696

5.0603 5.0172 4.9745 4.9324 4.8907

4.8496 4.8090 4.7690 4.7296 4.6908

5.0808 5.0377 4.9950 4.9528 4.9112

4.8701 4.8295 4.7895 4.7501 4.7114

5.1003 5.0573 5.0146 4.9725 4.9309

4.8897 4.8492 4.8092 4.7698 4.7310

5.1190 5.0759 5.0333 4.9912 4.9496 4.9085 4.8679 4.8279 4.7886 4.7498

5.1367 5.0936 5.0510 5.0089 4.9673

4.9262 4.8856 4.8457 4.8063 4.7675

5.1533 5.1102 5.0676 5.0255 4.9839

4.9428 4.9022 4.8622 4.8228 4.7841

5.1688 5.1257 5.0831 5.0410 4.9993

4.9582 4.9176 4.8776 4.8382 4.7994

5.1830 5.1399 5.0973 5.0551 5.0135

4.9723 4.9317 4.8917 4.8522 4.8134

5.1967 5.1536 5.1110 5.0688 5.0272

4.9860 4.9454 4.9054 4.8660 4.8272

5.2110 5.1679 5.1253 5.0832 5.0415 5.0004 4.9598 4.9198 4.8804 4.8416

5.2260 5.1829 5.1403 5.0982 5.0565 5.0154 4.9748 4.9348 4.8954 4.8566

5.2416 5.1985 5.1559 5.1138 5.0721 5.0310 4.9904 4.9504 4.9110 4.8721

5.2578 5.2147 5.1721 5.1300 5.0883 5.0472 5.0066 4.9666 4.9271 4.8883

5.2746 5.2315 5.1889 5.1467 5.1051

5.0639 5.0233 4.9833 4.9438 4.9050

5.2920 5.2489 5.2062 5.1641 5.1224 5.0812 5.0406 5.0005 4.9610 4.9222

5.3099 5.2668 5.2241 5.1819 5.1402 5.0990 5.0584 5.0183 4.9788 4.9399

5.3283 5.2852 5.2425 5.2003 5.1586 5.1173 5.0767 5.0366 4.9970 4.9581

5.3473 5.3041 5.2614 5.2191 5.1774 5.1361 5.0954 5.0553 5.0157 4.97

第三题

x=1:0.5:10;

y=x.^3-6*x.^2+5*x-3;

y0=y+rand;

f1=polyfit(x,y0,1)%输出多项式系数

y1=polyval(f1,x);%计算各x点的拟合值

plot(x,y,'+',x,y1) grid on title('一次拟合曲线'); figure(2);

f2=polyfit(x,y0,2)%2次多项式拟合