How do you find unit vector perpendicular to plane: 6x-2y+3z+8=0?

2 Answers
Oct 8, 2016

Unit vector perpendicular to plane 6x-2y+3z+8=06x2y+3z+8=0 is (6/7,-2/7,3/7)(67,27,37)

Explanation:

If we have a plane ax+by+cz=dax+by+cz=d, the vector normal to the plane is given by (a,b,c)(a,b,c)

Hence as given plane is 6x-2y+3z+8=06x2y+3z+8=0 or 6x-2y+3z=-86x2y+3z=8

and vector normal to this plane is (6,-2,3)(6,2,3)

Now the magnitude of vector (6,-2,3)(6,2,3) is

sqrt(6^2+(-2)^2+3^2)=sqrt(36+4+9)=sqrt49=762+(2)2+32=36+4+9=49=7

Hence, unit vector perpendicular to plane 6x-2y+3z+8=06x2y+3z+8=0 is (6/7,-2/7,3/7)(67,27,37)

Oct 14, 2017

6/7veci-2/7vecj+3/7veck67i27j+37k

Explanation:

we can find a perpendicular vector by using the result

that phi(x,y,z)=0=>gradphi(x,y,z)ϕ(x,y,z)=0ϕ(x,y,z)is a vector perpendicular to the plane

where grad is the del operator and is defined as:

grad-=vecidel/(dx)+vecjdel/(dely)+veckdel/(delz)idx+jy+kz

remembering that when we partially differentiate wrt a variable we treat the other variables as constant

phi(x,y,z)=6x-2y+3z+8=0ϕ(x,y,z)=6x2y+3z+8=0

:.gradphi(x,y,z)=

vecidel/(delx)(6x-2y+3z+8)

+vecjdel/(dely)(6x-2y+3z+8)

+veckdel/(delz)(6x-2y+3z+8)

=6veci-2vecj+3veck

call this vecn

then a unit vector is

hatvecn=vecn/|vecn|

:.hatvecn=(6veci-2vecj+3veck)/(sqrt(6^2+2^2+3^2))

=(6veci-2vecj+3veck)/7

=6/7veci-2/7vecj+3/7veck