Show that a Parametric Equation Maps To Another Line By Linear Transformation.

Click For Summary

Discussion Overview

The discussion revolves around the problem of demonstrating how a linear transformation maps a parametric equation representing a line in \(\mathbb{R}^n\) to another line or a single point. The focus is on the properties of linear transformations and their effects on geometric representations.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • The initial post presents a solution showing that a linear transformation \(T\) maps the line defined by \(\textbf{x} = \textbf{p} + t\textbf{v}\) to another line or a single point, depending on whether \(T\textbf{v} = \textbf{0}\).
  • Some participants suggest that the conclusion drawn may not always result in a line, emphasizing the need to consider degenerate cases where the transformation results in a single point.
  • A later reply indicates that the solution has been improved to address the concerns raised about the degenerate case.

Areas of Agreement / Disagreement

Participants express differing views on whether the mapping always results in a line, with some emphasizing the importance of considering degenerate cases. The discussion reflects a lack of consensus on the completeness of the initial solution.

Contextual Notes

The discussion highlights the need for clarity regarding the conditions under which the mapping occurs, particularly in cases where the transformation leads to a single point rather than a line.

bwpbruce
Messages
60
Reaction score
1
$\textbf{Problem}$
Given $\textbf{v} \ne \textbf{0}$ and $\textbf{p}$ in $\mathbb{R}^n$, the line through $\textbf{p}$ in the direction of $\textbf{v}$ is given by $\textbf{x} = \textbf{p} + t\textbf{v}$. Show that linear transformation $T: \mathbb{R}^n \rightarrow \mathbb{R}^n$ maps this line onto another line or onto a single point.

$\textbf{My Solution}$:
$\textbf{x} = \textbf{p} + t\textbf{v}$

By Linear Transformation Property:
$T(\textbf{x}) =T(\textbf{p} + t\textbf{v})$
$T(\textbf{x}) =T\textbf{p} + t(T\textbf{v})$

Let $T(\textbf{x}) = \textbf{y}, T\textbf{p} = \textbf{q}, T\textbf{v} = \textbf{w}$
Then $\textbf{y} = \textbf{q} + t\textbf{w}$ is another parametric equation and $\textbf{y}$ is the other line that $\textbf{x}$ maps to except in the case where $\textbf{w} = \textbf{0}$. Then $\textbf{y} = \textbf{q}$

Result:
$\textbf{y} = \textbf{q} + t\textbf{w}$

or

$\textbf{y} = \textbf{q}$

Conclusion:
$\textbf{x} \mapsto \textbf{y}$ by $T$.

Check my solution please?
 
Last edited:
Physics news on Phys.org
Hi,

It's almost correct, but $y$ doesn't need to be a line, read again the statement and fill the degenrate case.
 
Fallen Angel said:
Hi,

It's almost correct, but $y$ doesn't need to be a line, read again the statement and fill the degenrate case.

Is that better?
 
Yes, now is completely correct :D
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 0 ·
Replies
0
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K