Identical planes or not?

superwolf

Is plane (1 1 2) identical to (-1 -1 -2), or are they just parallel?

Related Calculus and Beyond Homework Help News on Phys.org

KLoux

The two vectors you supplied lie along the same line, right? But that's not enough to know if the planes are the same or not.

-Kerry

superwolf

They are not vectors, but two planes in a crystal.

phyzmatix

(1, 1, 2) and (-1, -1, -2) aren't planes. They can represent either vectors, or simply two separate points in three-space.

I agree with Kerry, you need more information to know how the planes in which these vectors/points lie relate to each other.

KLoux

They are not vectors, but two planes in a crystal.
Ahh... you should have mentioned that you are referring to materials science. We thought you were talking about mathematical planes...

Anyway, those are vectors, they're just used to identify crystalline planes. It's been a few years since I've had materials science, but I would say you probably still don't have enough information. They might be the same plane, they might be parallel, but why does it matter? What are you trying to solve? If you're trying to determine how a particular material will fail, then I would say that it doesn't matter. The vector refers to a direction, or a family of planes, not one specific plane.

-Kerry

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving