# Thread: what is the xy plane

1. ## what is the xy plane

Determine vector and parametric equations for the plane through the point (1, -2, 3) and parallel to the xy-plane
i understand the equations but what is the x-y plane????

2. ## Re: what is the xy plane

Originally Posted by flammingKnife95
Determine vector and parametric equations for the plane through the point (1, -2, 3) and parallel to the xy-plane i understand the equations but what is the x-y plane????

The $\displaystyle xy\text{-plane }$ is simply $\displaystyle z=0$. So what is the answer to this question?

3. ## Re: what is the xy plane

what are the x and y equal to?

4. ## Re: what is the xy plane

Originally Posted by flammingKnife95
what are the x and y equal to?
Does it matter? Isn't the x-y plane (z = 0) just moved up by 3 units so that it can go through the point (1, -2, 3)?

5. ## Re: what is the xy plane

Flamming...
you need a plane that passes through the point P(1,-2,3) and it is parallel to the plane XY.
to define a plane you need 2 things...
1 one point ...you have it

2 one vector that is perpendicular to the plane..
in your case....the plane XY is parallel to your plane and the vector v(0i+0j+1k) is perpendicular to the plane XY
therefore to define your plane get the point and the vector v and you are ok....

6. ## Re: what is the xy plane

Originally Posted by flammingKnife95
what are the x and y equal to?
$\displaystyle x~\&~y$ can be any real number whatsoever.

The $\displaystyle xy\text{-plane}=\{(x,y,0):\{x,y\}\subset\mathbb{R}\}$

7. ## Re: what is the xy plane

I forgot to mention that the equation of the plane you are looking is z = 3