Show that four points A, B, C and D whose position vectors are
`4hati+5hatj+hatk,-hatj-hatk-hatk, 3hati+9hatj+4hatk and 4(-hati+hatj+hatk)` respectively are coplanar.
The position vectors of the points A, B, C and D are `4hati+5hatj+hatk,-hatj-hatk, 3hati+9hatj+4hatk and 4(-hati+hatj+hatk)` , respectively. Then
The given points are coplanar iff vectors `vec(BA),vec(BC), vec(BD)` are coplanar
Hence, the four points A, B, C and D are coplanar.