[討論] rotation matrix A=y/x why wrong?

[polymerase (橋南荀令過，十里送衣香)]

大家好，我想請問為什麼A1 and A2都可以把x rotate到y但是

A1 ~= A2

A2是由y/x算出來的，是否也叫做rotation matrix?


clear all
clc
x=[1
   2
   3]
%A1 is  rotation matrix copied from wikipedia to rotate 30 degree around X
A1=[    1.0000         0         0
         0    0.8660    0.5000
         0   -0.5000    0.8660]
% y is the rotated matrix
     y1=A1*x

% A2 is y/x
A2=y1/x
% A2*x can recover y from x.
y2=A2*x
y2==y1


% but A2 is different then A1.
A2==A1

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推 physbook: x=[1;2;3] ?
推 sunev: A2^T*A2 ~= eye(3)
→ tn00364361: 可以去查查matlab的left division跟right division到
→ tn00364361: 底是在做什麼運算。