- #1
vibe3
- 46
- 1
I have two n-vectors [itex]e_1, e_2[/itex] which span a 2D subspace of [itex]R^n[/itex]:
[tex]
V = span\{e_1,e_2\}
[/tex]
The vectors [itex]e_1,e_2[/itex] are not necessarily orthogonal (but they are not parallel so we know its a 2D and not a 1D subspace). Now I also have a linear map:
[tex]
f: V \rightarrow W \\
f(v) = A v
[/tex]
where [itex]A[/itex] is a given [itex]n \times n[/itex] invertible matrix.
My question is: how would I construct an orthonormal basis for the space [itex]W[/itex]?
My thinking is to perform a QR decomposition on the [itex]n \times 2[/itex] matrix
[tex]
\left(
\begin{array}{cc}
A e_1 & A e_2
\end{array}
\right)
[/tex]
and then the columns of [itex]Q[/itex] will be an orthonormal basis for [itex]W[/itex]. Is this a correct solution? I'm not entirely sure since [itex]e_1,e_2[/itex] are not orthonormal.
[tex]
V = span\{e_1,e_2\}
[/tex]
The vectors [itex]e_1,e_2[/itex] are not necessarily orthogonal (but they are not parallel so we know its a 2D and not a 1D subspace). Now I also have a linear map:
[tex]
f: V \rightarrow W \\
f(v) = A v
[/tex]
where [itex]A[/itex] is a given [itex]n \times n[/itex] invertible matrix.
My question is: how would I construct an orthonormal basis for the space [itex]W[/itex]?
My thinking is to perform a QR decomposition on the [itex]n \times 2[/itex] matrix
[tex]
\left(
\begin{array}{cc}
A e_1 & A e_2
\end{array}
\right)
[/tex]
and then the columns of [itex]Q[/itex] will be an orthonormal basis for [itex]W[/itex]. Is this a correct solution? I'm not entirely sure since [itex]e_1,e_2[/itex] are not orthonormal.