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Vector Algebra question

2021 · 25 Feb · Shift 1 · Q44

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PYQ Library
JEE Main
Mathematics
Vector Algebra
2021 · 25 Feb · Shift 1 · Q44

Vector Algebra question

2021 · 25 Feb · Shift 1 · Q44

JEE MainMathematicsVector AlgebraNumerical+4 / −1

Let

\overrightarrow a = \widehat i + 2\widehat j - \widehat k

,

\overrightarrow b = \widehat i - \widehat j

and

\overrightarrow c = \widehat i - \widehat j - \widehat k

be three given vectors. If

\overrightarrow r

is a vector such that

\overrightarrow r \times \overrightarrow a = \overrightarrow c \times \overrightarrow a

and

\overrightarrow r .\,\overrightarrow b = 0

, then

\overrightarrow r .\,\overrightarrow a

is equal to

\underline{\hspace{2cm}}

.

Numerical answer

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