Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Vectors

Question:

Let a, b, c, be distinct and non-negative. If the vectors ai + aj + ck, i + k, and ci + cj + bk lie in a plane, then c is

Options:

A.M. of a and b

G.M. of a and b

H.M of a and b

equal to zero

Correct Answer:

G.M. of a and b

Explanation:

$\left|\begin{array}{lll}a & a & c \\ 1 & 0 & 1 \\ c & c & b\end{array}\right|=0$

$C_2 \rightarrow C_2-C_1$

$-1\left(a b-c^2\right)=0 \Rightarrow c^2=a b$

Hence (2) is correct answer.