MATLAB编程练习（含答案很好的）(3)

A=[34 44 23;8 34 23;34 55 2] A =

34 44 23 8 34 23 34 55 2

>> tril(A) ans =

34 0 8 34 34 55

>> triu(A)

ans =

34 44 0 34 0 0

>> diag(A)

ans =

34 34 2 norm(A) ans =

94.5106

>> rank(A) ans =

3

0 0 2 23 23 2 11

>> det(A)

ans =

-23462

>> trace(A)

ans = 70

>> null(A) ans =

Empty matrix: 3-by-0

>> eig(A) ans =

80.1587 12.7671 -22.9257

>> poly(A)

ans =

1.0e+004 *

0.0001 -0.0070 -0.1107 2.3462

>> logm(A)

Warning: Principal matrix logarithm is not defined for A with nonpositive real eigenvalues. A non-principal matrix logarithm is returned. > In funm at 153 In logm at 27

ans =

3.1909 + 0.1314i 1.2707 + 0.1437i 0.5011 - 0.2538i

12

0.4648 + 0.4974i 3.3955 + 0.5438i 0.1504 - 0.9608i 0.2935 - 1.2769i 0.8069 - 1.3960i 3.4768 + 2.4663i

>> fumn(A)

??? Undefined command/function 'fumn'.

>> inv(A)

ans =

0.0510 -0.0502 -0.0098 -0.0326 0.0304 0.0255 0.0305 0.0159 -0.0343

>> cond(A)

ans =

8.5072

>> chol(A)

??? Error using ==> chol

Matrix must be positive definite.

>> lu(A)

ans =

34.0000 44.0000 23.0000 0.2353 23.6471 17.5882 1.0000 0.4652 -29.1816

>> pinv(A) ans =

0.0510 -0.0502 -0.0098 -0.0326 0.0304 0.0255 0.0305 0.0159 -0.0343

>> svd(A)

ans =

13

94.5106 22.3456 11.1095

>> expm(A) ans =

1.0e+034 *

2.1897 4.3968 1.9382 1.3154 2.6412 1.1643 1.8782 3.7712 1.6625

>> sqrtm(A)

ans =

5.2379 + 0.2003i 3.4795 + 0.2190i 1.8946 - 0.3869i 0.5241 + 0.7581i 5.1429 + 0.8288i 2.0575 - 1.4644i 3.0084 - 1.9461i 4.7123 - 2.1276i 2.1454 + 3.7589i >>

016多项式的计算：

A=[34 44 23;8 34 23;34 55 2] A =

34 44 23 8 34 23 34 55 2

>> P=poly(A) P =

1.0e+004 *

0.0001 -0.0070 -0.1107 2.3462

14

>> PPA=poly2str(P,'X')

PPA =

X^3 - 70 X^2 - 1107 X + 23462

017多项式的运算： p=[2 6 8 3];w=[32 56 0 2]; >> m=conv(p,w) m =

64 304 592 548

>> [q,r]=deconv(w,p) q = 16 r =

0 -40 -128 -46

>> dp=polyder(w) dp =

96 112 0

>> [num,den]=polyder(w,p)

num =

80 512 724 312 den =

4 24 68 108

180 16 -16 100 48 6 9 15