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Vector Algebra question

2022 · 27 Jul · Shift 1 · Q34

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JEE Main
Mathematics
Vector Algebra
2022 · 27 Jul · Shift 1 · Q34

Vector Algebra question

2022 · 27 Jul · Shift 1 · Q34

JEE MainMathematicsVector AlgebraMCQ+4 / −1

Let

\vec{a}=\alpha \hat{i}+\hat{j}+\beta \hat{k}

and

\vec{b}=3 \hat{i}-5 \hat{j}+4 \hat{k}

be two vectors, such that

\vec{a} \times \vec{b}=-\hat{i}+9 \hat{j}+12 \hat{k}

. Then the projection of

\vec{b}-2 \vec{a}

on

\vec{b}+\vec{a}

is equal to :

A
2
B
$\frac{39}{5}$
C
9
D
$\frac{46}{5}$

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