Matlab与数学建模综合练习(7)

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??2004200?0200430（７）??002004?000??000>> D=[20:10:50]'

D =

20 30 40 50

>> D=diag(D,1) D =

0 20 0 0 0 0 0 30 0 0 0 0 0 40 0 0 0 0 0 50 0 0 0 0 0

>> V=diag(2004*ones(5,1)) V =

2004 0 0 0 2004 0 0 0 2004 0 0 0 0 0 0

>> D+V

ans =

2004 20 0 0 2004 30 0 0 2004 0 0 0 0 0 0 00?00?400??200450? ?02004?? 0 0 0 0 0 0 2004 0 0 2004

0 0 0 0 40 0 2004 50 0 2004

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程序式：

A=zeros(5); for i=1:5 for j=1:5 if i==j

A(i,j)=2004; elseif i+1==j A(i,j)=10*j; else

A(i,j)=0; end end end A 运行结果: A =

2004 20 0 0 0 0 2004 30 0 0 0 0 2004 40 0 0 0 0 2004 50 0 0 0 0 2004

6．绘制下列曲线的图形（散点图与折线图）：y?>> x=[-1:0.1:2];

>> y=(x.^3-x.^2-x+1).^(1/3); >> plot(x,y,'.')

3x3?x2?x?1,x?[?1,2]

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