Determining if a line is perpendicular in ##R^3##

In summary, the question asks if the line passing through (-2, 4, 0) and (1, 1, 1) is perpendicular to the line passing through (2, 3, 4) and (3, -1, -8). The equations R = R0 + tV (for each line) are provided. The attempt at a solution involves checking if the two V vectors are proportional for parallel lines and using the dot product or cross product for perpendicular lines. It is also noted that the lines should intersect to avoid being skew lines.
  • #1
Calpalned
297
6

Homework Statement


Is the line through (-2, 4, 0) and (1, 1, 1) perpendicular to the line through (2, 3, 4) and (3, -1, -8)?

Homework Equations


R = R0 + tV (for each line)

The Attempt at a Solution


If the lines are parallel, then the V for the two equations will be proportional to each other. How are the two V's related if they are perpendicular?
 
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  • #2
Calpalned said:

Homework Statement


Is the line through (-2, 4, 0) and (1, 1, 1) perpendicular to the line through (2, 3, 4) and (3, -1, -8)?

Homework Equations


R = R0 + tV (for each line)

The Attempt at a Solution


If the lines are parallel, then the V for the two equations will be proportional to each other. How are the two V's related if they are perpendicular?

Think dot product.
 
  • #3
I see thank you, Dick.
 
  • #4
You could also use the cross product if you prefer that.
 
  • #5
Brian T said:
You could also use the cross product if you prefer that.

And you don't mind doing at least three times as much work...
 
  • #6
:-p
 
  • #7
You might also want to be sure that the lines intersect and thus are not skew lines.
 

FAQ: Determining if a line is perpendicular in ##R^3##

How do you determine if two lines are perpendicular in ##R^3##?

In order for two lines to be perpendicular in ##R^3##, their direction vectors must be perpendicular to each other. This means that the dot product of the two direction vectors must equal 0.

Can you visually determine if two lines are perpendicular in ##R^3##?

Yes, you can visually determine if two lines are perpendicular in ##R^3## by looking at their direction vectors. If the direction vectors are at a 90 degree angle to each other, then the lines are perpendicular.

How can you represent two lines in ##R^3## mathematically?

Two lines in ##R^3## can be represented as parametric equations, where each line has a direction vector and a point on the line. These equations can then be used to determine if the lines are perpendicular.

What is the significance of finding two perpendicular lines in ##R^3##?

Finding two perpendicular lines in ##R^3## can be useful in determining the orientation of objects or in solving geometric problems. It can also be used in applications such as computer graphics and engineering.

Are there any special cases in determining if two lines are perpendicular in ##R^3##?

Yes, there are special cases where the direction vectors of the lines are parallel or when one or both lines are undefined (such as a vertical line). In these cases, the lines are not perpendicular and the dot product will not equal 0.

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