Understanding Projection: Clarifying Confusion in Orthogonal Projections

In summary, the conversation discusses the conditions for a projection to be considered orthogonal. The question asks if a projection that satisfies a certain norm inequality is necessarily orthogonal. The individual also shares their own example of projecting a vector onto a line and questions if they are doing it correctly.
  • #1
holezch
251
0

Homework Statement


Hi, I got tied up with something..
I have a question that says if a projection P satisfies || P v || <= || v ||
then P is an orthogonal projection.. but if I drew in |R^2, a x-axis and a y=x line, and projected some vector onto the y = x line.. I still get || Pv || <= || V || ? I think Iam doing something wrong

thanks
 
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  • #2
When you say you project V onto the y = x line, are you projecting it perpendicular to the line? I mean thinking of the tip of V projecting perpendicularly to the line? And if so, what's the problem? If you are projecting, for example, vertically to the line then you don't have your norm inequality.
 

Related to Understanding Projection: Clarifying Confusion in Orthogonal Projections

1. What is a projection in mathematics?

A projection in mathematics is a mathematical operation that maps a point or set of points onto a lower dimensional space. This is often done in order to simplify a problem or to visualize data in a more easily interpretable way.

2. What is an orthogonal projection?

An orthogonal projection is a type of projection where the projected vector is perpendicular to the projection plane. This means that the projected vector forms a right angle with the projection plane, resulting in a 2-dimensional image that is as close to the original 3-dimensional object as possible.

3. How is orthogonal projection different from other types of projections?

Orthogonal projection is different from other types of projections in that it preserves the distances between points in the original object, whereas other types of projections may distort the distances. It is also unique in that the projected vector is perpendicular to the projection plane.

4. What is the purpose of understanding projection in mathematics?

Understanding projection in mathematics is important because it allows for the simplification of complex problems and the visualization of data in a more meaningful way. It is also a fundamental concept in geometry and can be applied in various fields such as physics, engineering, and computer graphics.

5. How can I improve my understanding of projection?

To improve your understanding of projection, it is important to first have a strong understanding of basic mathematics concepts such as vectors and matrices. You can also practice with different types of projections, visualize them, and apply them to real-life problems. Additionally, seeking guidance from a teacher or working through practice problems can also help improve your understanding.

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