New chat PYQ Library Doubts Rank report

Sign in to see Recents

Sign in to save progress →

Vector Algebra question

2021 · 25 Jul · Shift 2 · Q31

Guest · try one question or challengeGuest · try one question or challenge

PYQ Library
JEE Main
Mathematics
Vector Algebra
2021 · 25 Jul · Shift 2 · Q31

Vector Algebra question

2021 · 25 Jul · Shift 2 · Q31

JEE MainMathematicsVector AlgebraMCQ+4 / −1

Let a, b and c be distinct positive numbers. If the vectors

a\widehat i + a\widehat j + c\widehat k,\widehat i+\widehat k

and

c\widehat i + c\widehat j + b\widehat k

are co-planar, then c is equal to :

A
${2 \over {{1 \over a} + {1 \over b}}}$
B
${{a + b} \over 2}$
C
${1 \over a} + {1 \over b}$
D
$\sqrt {ab}$

More from Vector Algebra

If $a = 2, b = 5$ and $a \times b$ = 8, then $a . b$ is equal to :2021 · MCQ
If $(a + 3 b)$ is perpendicular to $(7 a - 5 b)$ and $(a - 4 b)$ is perpendicular to $(7 a - 2 b)$ …2021 · Numerical
A hall has a square floor of dimension 10 m $\times$ 10 m (see the figure) and vertical walls. If the angle GPH between the diagonals AG and BH is $cos^{- 1} \frac{1}{5}$ , then the height of the hall (in meters) is : Includes diagram2021 · MCQ
If the projection of the vector $i + 2 j + k$ on the sum of the two vectors $2 i + 4 j - 5 k$ and $- λ i + 2 j + 3 k$ is 1, then $λ$ is equal to …2021 · Numerical
If vectors $a_{1} = x i - j + k$ and $a_{2} = i + y j + z k$ are collinear, then a possible unit vector parallel to the vector $x i + y j + z k$ …2021 · MCQ
Let $a = i + 5 j + α k$ , $b = i + 3 j + β k$ and $c = - i + 2 j - 3 k$ be three vectors such that, $b \times c = 53$ …2021 · Numerical
Let $a = i + j + 2 k$ and $b = - i + 2 j + 3 k$ . Then the vector product $(a + b) \times ((a \times ((a - b) \times b)) \times b)$ …2021 · MCQ
Let $a = i + j + k, b$ and $c = j - k$ be three vectors such that $a \times b = c$ and $a . b = 1$ …2021 · Numerical