关于matlab矩阵乘法的问题A=[cos(x)0sin(x);010;-sin(x)0cos(x)];B=[cos(y)sin(y)0;-sin(y)cos(y)0;001];这两个矩阵怎么算乘法?

Question

关于matlab矩阵乘法的问题
A=[cos(x) 0 sin(x);0 1 0;-sin(x) 0 cos(x)]; B=[cos(y) sin(y) 0;-sin(y) cos(y) 0;0 0 1]; 这两个矩阵怎么算乘法?

Answer 1

这个就要根据你的需求了,matlab中矩阵相乘有两种,一种是点乘,即A.*B,还有一种是直接乘,即A*B.点乘是两个矩阵之间对应坐标之间的元素相乘,而直接乘,就是按照矩阵乘法的法则里计算的.
给出源代码如下：
>> syms x y
>> A=[cos(x) 0 sin(x);0 1 0;-sin(x) 0 cos(x)];
>> B=[cos(y) sin(y) 0;-sin(y) cos(y) 0;0 0 1];
>> C1=A.*B;
>> C2=A*B;
>> C1
C1 =
[cos(y) cos(x) 0 0 ]
[ ]
[ 0 cos(y) 0 ]
[ ]
[ 0 0 cos(x)]
>> C2
C2 =
[cos(y) cos(x) cos(x) sin(y) sin(x)]
[ ]
[ -sin(y) cos(y) 0 ]
[ ]
[-sin(x) cos(y) -sin(x) sin(y) cos(x)]