Let a, b and c be distinct positive numbers. If... | Vectors | JEE Main 2021

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JEE MAIN 2021

25-07-2021 S2

Question

Let $a, b$ and $c$ be distinct positive numbers. If the vectors $a-a \hat{i}+a \hat{j}+c \hat{k}, \hat{i}+\hat{k}$ and $c \hat{i}+c \hat{j}+b \hat{k}$ are co-planar, then c is equal to:

Select the correct option:

A

$\frac{2}{\frac{1}{a}+\frac{1}{b}}$

B

$\frac{a+b}{2}$

C

$\frac{1}{a}+\frac{1}{b}$

D

$\sqrt{a b}$

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