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Vector Algebra question

2022 · 28 Jul · Shift 1 · Q27

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JEE Main
Mathematics
Vector Algebra
2022 · 28 Jul · Shift 1 · Q27

Vector Algebra question

2022 · 28 Jul · Shift 1 · Q27

JEE MainMathematicsVector AlgebraMCQ+4 / −1

Let a vector

\vec{a}

has magnitude 9. Let a vector

\vec{b}

be such that for every

(x, y) \in \mathbf{R} \times \mathbf{R}-\{(0,0)\}

, the vector

(x \vec{a}+y \vec{b})

is perpendicular to the vector

(6 y \vec{a}-18 x \vec{b})

. Then the value of

|\vec{a} \times \vec{b}|

is equal to :

A
$9 \sqrt{3}$
B
$27 \sqrt{3}$
C
9
D
81

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