Find the unit vector perpendicular to a and b

1. May 20, 2007

anantchowdhary

1. The problem statement, all variables and given/known data
there are two vectors a and b

a=3i+2j+k
b=2i+j+2k

Find the unit vector perpendicular to a and b

2. Relevant equations

| A|^a=A
3. The attempt at a solution

I dont kno how to start

2. May 20, 2007

neurocomp2003

go to mathworld.com and find what it means to be a perpendicular vector to
2 other vectors.

3. May 20, 2007

cristo

Staff Emeritus
Well, calling the third vector c=(l,m,n), you should be able to find 3 equations. They will come from the facts that (i) a is perpendicular to c, (ii) b is perpendicular to c, and (iii) c is a unit vector.

4. May 20, 2007

anantchowdhary

i tried to use the dot product and cross product but i still couldnt get the answer

5. May 20, 2007

cristo

Staff Emeritus
Well what did you try?

6. May 20, 2007

malawi_glenn

Do you know the properties of vector (cross) product ?
and this is precalculus math, not physics

7. May 22, 2007

genius_me

try using crossproduct,

a x b = resultant(r)
divide a x b by the magnitude of r,
u will get ur unit vector

8. Jun 26, 2007

krateesh

ya axb..will give us vector whose unit vector is required

9. Jun 26, 2007

anantchowdhary

yea..thnx....gt the answer long ago! thnx nywyz

help much appreciated