用rand(n,m)函数生成一个5*5 矩阵A,并且计算它的范数

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>> A=rand(5,5)
A =
0.9501 0.7621 0.6154 0.4057 0.0579
0.2311 0.4565 0.7919 0.9355 0.3529
0.6068 0.0185 0.9218 0.9169 0.8132
0.4860 0.8214 0.7382 0.4103 0.0099
0.8913 0.4447 0.1763 0.8936 0.1389
>> s1=abs(A)
s1 =
0.9501 0.7621 0.6154 0.4057 0.0579
0.2311 0.4565 0.7919 0.9355 0.3529
0.6068 0.0185 0.9218 0.9169 0.8132
0.4860 0.8214 0.7382 0.4103 0.0099
0.8913 0.4447 0.1763 0.8936 0.1389
>> a=A(2,1)
a =
0.2311
>> A(2,3)=5
A =
0.9501 0.7621 0.6154 0.4057 0.0579
0.2311 0.4565 5.0000 0.9355 0.3529
0.6068 0.0185 0.9218 0.9169 0.8132
0.4860 0.8214 0.7382 0.4103 0.0099
0.8913 0.4447 0.1763 0.8936 0.1389
>> B=sum(A)
B =
3.1654 2.5032 7.4517 3.5620 1.3727
>> max(B)
ans =
7.4517