- #1
FaraDazed
- 347
- 2
Homework Statement
Prove that the vectors a=(3,2,-1), b=(5,-7,3), c=(11, -3, 1) are coplanar.
Homework Equations
not sure
The Attempt at a Solution
First time I have ever came across the term coplanar, I know what it means but did not know any tests for it. So I did a little research and found that one way is to test if they are linearly independent and that if that are not linearly independent then that means they must be coplanar.
So where I found this out, it had a few example of testing for linearly independency using the determent of a matrix formed by the three vectors (as column vectors) and I think I have done it correct as my answer comes out to zero. But as I am extremely new to this (the past half hour or so) I wanted a second opinion.
[itex]
Det \begin{vmatrix}
3 & 5 & 11 \\
2 & -7 & 3 \\
-1 & 3 & 1
\end{vmatrix}
=3(-7+9)-5(2-3)+11(6-7) = 6+5+(-11)=0
[/itex]
And therefore as the determent is zero, that means they are NOT linearly independent, and hence means that they are coplanar. At least this is what I have gathered from a little bit of research.
Appreciate it if someone could double check the thinking behind the method. Thanks :)
Last edited: