The direction cosines of the perpendicular from the origin to the plane `vecr.(6hati-3hatj-2hatk)+1=0` are

Options

A. `6/7,3/7,-2/7`
B. `6/7,-3/7,2/7`
C. `-6/7,3/7,2/7`
D. none of these

Answer

c

Explanation

Given planes is `vecr.(-6hati+3hatj+2hatk)=1`.
`therefore vecr.vecn=p`, where `vecn=(-6hati+3hatj+2hatk)`.
D.r.'s of the normal to the given plane are `-6,3,2` and `sqrt((-6)^(2)+3^(2)+2^(2))=sqrt(49)=7`.
`therefore` d.c's of the normal to the given plane ar e`-6/7, 3/7,2/7`.