怎么用matlab求一个矩阵的的值 matlab求矩阵中某一个值的个数怎么写?
matlab\u4e2d\u5982\u4f55\u53d6\u51fa\u77e9\u9635\u4e2d\u7684\u67d0\u4e00\u4e2a\u503cmatlab\u6c42\u77e9\u9635\u4e2d\u67d0\u4e00\u4e2a\u503c\u7684\u4e2a\u6570\u6709\u4e09\u79cd\u65b9\u6cd5\uff1a
1\u3001\u4f8b\u5982\u5f53A=ceil(rand(100,100)*10); a=5; \u7b2c\u4e00\u79cd\u65b9\u6cd5\u4e3a\u8f93\u5165\uff1a sum(A(:)==a)\uff1b
2\u3001\u7b2c\u4e8c\u79cd\u65b9\u6cd5\u4e3a\u8f93\u5165\uff1a length(find(A==a)\u3002
3\u3001\u7b2c\u4e09\u79cd\u65b9\u6cd5\u4e3a\u8f93\u5165\uff1a logical=(A=a)\u3002
4\u3001\u6700\u540e\u4ee5sum(logical(:))\u7ed3\u5c3e\u5373\u53ef\u5b8c\u6210\u4ee3\u7801\u7684\u7f16\u5199\u3002
\u6269\u5c55\u8d44\u6599\uff1a
Matlab\u77e9\u9635\u8fd0\u7b97\u89c4\u5219\uff1a
1\u3001\u52a0\u51cf\u8fd0\u7b97\u89c4\u5219\uff1a\u5bf9\u5e94\u5143\u7d20\u76f8\u52a0\u3001\u51cf\uff0c\u5373\u6309\u7ebf\u6027\u4ee3\u6570\u4e2d\u77e9\u9635\u7684\u201c\u5341\u201d\uff0c\u201c\u4e00\u201d\u8fd0\u7b97\u8fdb\u884c\u3002
\u4f8b >>A=[1, 1, 1; 1, 2, 3; 1, 3, 6]
>>B=[8, 1, 6; 3, 5, 7; 4, 9, 2]
>>A\uff0bB=A+B
>>A-B=A-B
2\u3001\u4e58\u6cd5\u8fd0\u7b97\u89c4\u5219\uff1a\u6309\u7ebf\u6027\u4ee3\u6570\u4e2d\u77e9\u9635\u4e58\u6cd5\u8fd0\u7b97\u8fdb\u884c\uff0c\u5373\u653e\u5728\u524d\u9762\u7684\u77e9\u9635\u7684\u5404\u884c\u5143\u7d20\uff0c\u5206\u522b\u4e0e\u653e\u5728\u540e\u9762\u7684\u77e9\u9635\u7684\u5404\u5217\u5143\u7d20\u5bf9\u5e94\u76f8\u4e58\u5e76\u76f8\u52a0\u3002
\u4f8b >>X= [2 3 4 5;
1 2 2 1]\uff1b
>>Y=[0 1 1;
1 1 0;
0 0 1;
1 0 0]\uff1b
Z=X*Y
3\u3001\u77e9\u9635\u8f6c\u7f6e\u8fd0\u7b97\u89c4\u5219\uff1a\u82e5\u77e9\u9635A\u7684\u5143\u7d20\u4e3a\u5b9e\u6570\uff0c\u5219\u4e0e\u7ebf\u6027\u4ee3\u6570\u4e2d\u77e9\u9635\u7684\u8f6c\u7f6e\u76f8\u540c\u3002\u82e5A\u4e3a\u590d\u6570\u77e9\u9635\uff0c\u5219A\u8f6c\u7f6e\u540e\u7684\u5143\u7d20\u7531A\u5bf9\u5e94\u5143\u7d20\u7684\u5171\u8f6d\u590d\u6570\u6784\u6210\u3002\u82e5\u4ec5\u5e0c\u671b\u8f6c\u7f6e\uff0c\u5219\u7528\u5982\u4e0b\u547d\u4ee4\uff1aA.\u2032\u3002
使用det命令即可求解行列式的值。
具体示例如下：
A = [1 -2 4; -5 2 0; 1 0 3]
d = det(A)
结果为：
A =
1 -2 4
-5 2 0
1 0 3
d =
-32
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