Find the cosine of the angle between the normals to the planes

[whig4life]

1. Homework Statement

Find the cosine of the angle between the normals to the planes:

x+y+2z=3 and 2x-y+2z=5

2. Homework Equations [/b]

x+y+2z=3 and 2x-y+2z=5

3. The Attempt at a Solution

All I know is cos θ= V * W / ||V|| ||W||

 

[Dick]

1. Homework Statement

Find the cosine of the angle between the normals to the planes:

x+y+2z=3 and 2x-y+2z=5

2. Homework Equations [/b]

x+y+2z=3 and 2x-y+2z=5

3. The Attempt at a Solution

All I know is cos θ= V * W / ||V|| ||W||

The first step is to find the vectors that are normal to the planes. If you don't know how to do that try and look it up.

 

[Dick]

It's pretty simple. Look here for example http://mathworld.wolfram.com/NormalVector.html