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1
JEE Main 2021 (Online) 25th July Morning Shift
+4
-1
Let the vectors

$$(2 + a + b)\widehat i + (a + 2b + c)\widehat j - (b + c)\widehat k,(1 + b)\widehat i + 2b\widehat j - b\widehat k$$ and $$(2 + b)\widehat i + 2b\widehat j + (1 - b)\widehat k$$ $$a,b,c, \in R$$ be co-planar. Then which of the following is true?
A
2b = a + c
B
3c = a + b
C
a = b + 2c
D
2a = b + c
2
JEE Main 2021 (Online) 25th July Morning Shift
+4
-1
Let the foot of perpendicular from a point P(1, 2, $$-$$1) to the straight line $$L:{x \over 1} = {y \over 0} = {z \over { - 1}}$$ be N. Let a line be drawn from P parallel to the plane x + y + 2z = 0 which meets L at point Q. If $$\alpha$$ is the acute angle between the lines PN and PQ, then cos$$\alpha$$ is equal to ________________.
A
$${1 \over {\sqrt 5 }}$$
B
$${{\sqrt 3 } \over 2}$$
C
$${1 \over {\sqrt 3 }}$$
D
$${1 \over {2\sqrt 3 }}$$
3
JEE Main 2021 (Online) 22th July Evening Shift
+4
-1
Let L be the line of intersection of planes $$\overrightarrow r .(\widehat i - \widehat j + 2\widehat k) = 2$$ and $$\overrightarrow r .(2\widehat i + \widehat j - \widehat k) = 2$$. If $$P(\alpha ,\beta ,\gamma )$$ is the foot of perpendicular on L from the point (1, 2, 0), then the value of $$35(\alpha + \beta + \gamma )$$ is equal to :
A
101
B
119
C
143
D
134
4
JEE Main 2021 (Online) 22th July Evening Shift
Let a vector $${\overrightarrow a }$$ be coplanar with vectors $$\overrightarrow b = 2\widehat i + \widehat j + \widehat k$$ and $$\overrightarrow c = \widehat i - \widehat j + \widehat k$$. If $${\overrightarrow a}$$ is perpendicular to $$\overrightarrow d = 3\widehat i + 2\widehat j + 6\widehat k$$, and $$\left| {\overrightarrow a } \right| = \sqrt {10}$$. Then a possible value of $$[\matrix{ {\overrightarrow a } & {\overrightarrow b } & {\overrightarrow c } \cr } ] + [\matrix{ {\overrightarrow a } & {\overrightarrow b } & {\overrightarrow d } \cr } ] + [\matrix{ {\overrightarrow a } & {\overrightarrow c } & {\overrightarrow d } \cr } ]$$ is equal to :
$$-$$42
$$-$$40
$$-$$29
$$-$$38