Question

Equation of a plane is `vecr (3hati-4hatj+12hatk)=8`. Find the length of the perpendicular from the origin to the plane.

Answer 1

`vecr (3hati-4hatj+12hatk)=8..........(i)`

`vecn=3hati-4hatj+12hatk`

`|vecn|=sqrt(9+16+144)=13`

`therefore vec n=(3 hati-4hatj+12hatk)/13`

`therefore vecr.((3 hati-4hatj+12hatk)/13)=8/13............ by(i)`

`vecr.vecn=p`

∴ Perpendicular distance from the origin is ` 8/13`