- #1
Benny
- 584
- 0
Hi, can someone help me get started on the following question?
Q. Show that there is no line in the real plane R^2 through the origin which is invariant under the transformation whose matrix is:
[tex]
A\left( \theta \right) = \left[ {\begin{array}{*{20}c}
{\cos \theta } & { - \sin \theta } \\
{\sin \theta } & {\cos \theta } \\
\end{array}} \right]
[/tex]
The problem is that I don't know what is meant by "invariant under the transformation." Another question asks for 1-dimesional subspaces of R^2 under the operation of the matrix [tex]\left[ {\begin{array}{*{20}c}
1 & 0 \\
2 & 0 \\
\end{array}} \right][/tex] .
The answer is span(0,1) and span(1,2). I don't know why those are the answers but with a little bit of guess work I decided to find the eigenspaces of the of the matrix and found that the two eigenspaces were exactly those answers. So is there some relationship between eigenspaces/ eigenvectors/ eigenvalues and invariance under transformations?
Q. Show that there is no line in the real plane R^2 through the origin which is invariant under the transformation whose matrix is:
[tex]
A\left( \theta \right) = \left[ {\begin{array}{*{20}c}
{\cos \theta } & { - \sin \theta } \\
{\sin \theta } & {\cos \theta } \\
\end{array}} \right]
[/tex]
The problem is that I don't know what is meant by "invariant under the transformation." Another question asks for 1-dimesional subspaces of R^2 under the operation of the matrix [tex]\left[ {\begin{array}{*{20}c}
1 & 0 \\
2 & 0 \\
\end{array}} \right][/tex] .
The answer is span(0,1) and span(1,2). I don't know why those are the answers but with a little bit of guess work I decided to find the eigenspaces of the of the matrix and found that the two eigenspaces were exactly those answers. So is there some relationship between eigenspaces/ eigenvectors/ eigenvalues and invariance under transformations?