JEE Main2012MathematicsVector AlgebraActual
Let A B C D be a parallelogram such that A B = q , A D = p and B A D be an acute angle. If r is the vector that coincides with the altitude directed from the vertex B to the side A D , then r is given by
Options
- Ar =3 q - 3( p q ) ( p p ) p
- Br =- q + ( p q p p ) p
- Cr = q - ( p q p p ) p
- Dr =-3 q + 3( p q ) ( p p ) p
Correct answer
B. r =- q + ( p q p p ) p
Step-by-step solution
AE = vector component of q on p AE = ( p q ) ( p q ) p From ABE ; AB + BE = AE q + r = ( p q ) p ( p q ) r =- q + ( p q ) ( p p ) p