Finding a plane that contains 2 lines.

In summary, the task is to find if there is a plane that contains two given parametric equations of lines and to find the equation of that plane. It is possible for two parallel lines to determine a plane, and the only case where two lines would not determine a plane is if they are skew lines. To find the equation of the plane, the parametric equations can be set equal to each other to find an intersection point.
  • #1
Kuma
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Homework Statement



I have 2 parametric equations of 2 lines. I want to find if there is a plane that contains both, if any, and find the equation.

Homework Equations





The Attempt at a Solution



so just thinking about it, I figure that a plane would contain both lines only if they intersect. Is that right?
if so, my second problem is finding the equation of the said plane. So for both the lines, do I plug in any value of t in the parametric equations to find 2 vectors, take the cross product to find a normal and use that for my equation?
 
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  • #2
Kuma said:

Homework Statement



I have 2 parametric equations of 2 lines. I want to find if there is a plane that contains both, if any, and find the equation.

Homework Equations





The Attempt at a Solution



so just thinking about it, I figure that a plane would contain both lines only if they intersect. Is that right?
No, you could have two parallel lines, and they would determine a plane. The only way two lines would not determine a plane is if they are skew lines - lines that aren't parallel and that don't intersect.

I'm assuming that you're working in three dimensions.
Kuma said:
if so, my second problem is finding the equation of the said plane. So for both the lines, do I plug in any value of t in the parametric equations to find 2 vectors, take the cross product to find a normal and use that for my equation?
 
  • #3
Mark44 said:
No, you could have two parallel lines, and they would determine a plane. The only way two lines would not determine a plane is if they are skew lines - lines that aren't parallel and that don't intersect.

I'm assuming that you're working in three dimensions.

thanks. Totally forgot about the parallel case. So I set my parametric equations equal to each other and found an intersection point. Yes this is in 3 dimensions
 

FAQ: Finding a plane that contains 2 lines.

What is the formula for finding a plane that contains 2 lines?

The formula for finding a plane that contains 2 lines is known as the cross product. It involves taking the cross product of the direction vectors of the two lines and using that to find a vector perpendicular to both lines, which can be used as the normal vector of the plane.

How many points are needed to uniquely determine a plane that contains 2 lines?

Three points are needed to uniquely determine a plane that contains 2 lines. These points can be chosen from the two lines, as long as they are not collinear.

Can the two lines be parallel and still lie on the same plane?

Yes, the two lines can be parallel and still lie on the same plane. In this case, the plane would be parallel to the two lines and would not intersect them.

Is it possible for the two lines to intersect and not lie on the same plane?

No, if the two lines intersect, then they must lie on the same plane. This is because the intersection point of the two lines can be used as one of the three points needed to uniquely determine a plane.

Are there any special cases when finding a plane that contains 2 lines?

There are a few special cases to consider when finding a plane that contains 2 lines. If the two lines are skew (do not intersect and are not parallel), then there is no unique solution for the plane. Also, if the two lines are coincident (lie on top of each other), then there are infinitely many planes that contain them.

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