Question

A vector a  has components 2p and 1 with respect to a rectangular Cartesian system. This system is rotated through a certain angle about the origin in the counter clockwise sense. If, with respect to the new system, vector a  has components p+1 and l, then

(A) p = 0 

(B) p=1 or p= - 1/3 

(C) p = -1 or p = 1/3

(D) p = 1 or p = -1  

Answer 1

Correct option (B) p=1 or p= -1/3

Explanation:

⇒ 3p(p - 1) + 1(p - 1) = 0

⇒ (p - 1)(3p + 1) = 0

⇒ p = 1, -1/3