Q.

Vectors ai^+bj^+k^ and 2i^3j^+4k^ are perpendicular to each other when 3a + 2b = 7, the ratio of a to b is x2. The value of x is ________ .          [2023]


Ans.

(1)

For two perpendicular vectors

(ai^+bj^+k^)·(2i^3j^+4k^)=0

2a – 3b + 4 = 0

on solving, 2a – 3b = –4

also given 3a + 2b = 7

We get a = 1, b = 2

ab=x2  x=2ab=2×12=1