Question

matlab 提示说内矩阵维度不一致。

方程：
function y=f(m1,m2,j)

g=9.8;
y=[0,m1*g,0,m2*g]'*inv([m1*cos(j),-m1,-sin(j),0;m1*sin(j),0,cos(j),0;0,m2,-sin(j),0;0,0,-cos(j),1])
y
结果：
>> hanshu(12,12,8)
??? Error using ==> mtimes
Inner matrix dimensions must agree.

Error in ==> hanshu at 3
y=[0,m1*g,0,m2*g]'*inv([m1*cos(j),-m1,-sin(j),0;m1*sin(j),0,cos(j),0;0,m2,-sin(j),0;0,0,-cos(j),1])

>>

Answer 1

[0,m1*g,0,m2*g]'

不要转置，直接[0,m1*g,0,m2*g]就好

追问

你好，

该题的原题为

如果不转置，[0,m1*g,0,m2*g]是一个一行的一位行向量？

追答

矩阵乘法规定的，第一个阵的列数必须与第二个阵的行数一致，否则matlab就提示出错。
不转置的话[0,m1*g,0,m2*g]是一个1行四列的向量
刚看了看原题，是不是为了求解X写的函数？
X=inv(A)*B,
矩阵乘法可没有交换律
try
y=inv([m1*cos(j),-m1,-sin(j),0;m1*sin(j),0,cos(j),0;0,m2,-sin(j),0;0,0,-cos(j),1])*[0,m1*g,0,m2*g]'