Check whether the given three vectors are coplnar or non- coplanar :
`-2hati -2 hatj + 4hatk, -2hati + 4hatj -2hatk, 4hati - 2hatj - 2hatk`.

Explanation

let `a=-2hati-2hatj+4hatk`
`b=-2hati+4hatj-2hatk and c=4hati-2hatj-2hatk`
Now, consider
`|(-2,-2,4),(-2,4,-2),(4,-2,-2)|=-2(-8-4)+2(4+8)+4(4-16)`
`=24+24-48=0`
`therefore`The vectors are complanar.