A vector a has components 3p 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 new system, a has components p + 1 and √10 , then a value of p is equal to:
(1) 1
(2) − 5/4
(3) 4/5
(4) -1
