Yes, that is what I thought you were saying but then I thought that the matrix multiplication was wrong. I am not sure why you switching addition confused me so much but I was wrong? You were right? I hope that SK has not been following this post.No. What I am saying is that
3x + 4y = 11
-3y + 2x = 22
is the same system as
3x + 4y = 11
2x - 3y = 22
And if linear algebra says that those are different, then linear algebra is nonsense.
I have this vague recollection that you need to order the variables consistently for purposes of linear algebra, but there is no point in relying on my half-baked recollections.
ROFLMAOYes, that is what I thought you were saying but then I thought that the matrix multiplication was wrong. I am not sure why you switching addition confused me so much but I was wrong? You were right? I hope that SK has not been following this post.
Seriously, your proof was nice (until I thought it was wrong).
Thanks for resolving that.\(\displaystyle
\begin{pmatrix}x'\\y'\end{pmatrix} = \begin{pmatrix}cos A & -sin A\\sin A & cos A\end{pmatrix} \begin{pmatrix}x\\y\end{pmatrix}\)
translates to:
\(\displaystyle x' = x cos A - y sin A\)
\(\displaystyle y' = x sin A + y cos A\)
which is what JeffM said back in post #2.
PS. Still haven't solved my lining up sin A issue. Anyone??