MEDIUM
JEE Main
IMPORTANT
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Let A, B, C be three points whose position vectors respectively are:

a=i^+4j^+3k^

b=2i^+αj^+4k^, αR

c=3i^-2j^+5k^

If α is the smallest positive integer for which a, b, c are non-collinear, then the length of the median of ABC through A is:

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Important Questions on Vector Algebra

MEDIUM
JEE Main
IMPORTANT
Let a=i^-2j^+3k^, b=i^+j^+k^ and c be a vector such that a×(b+c)=0, then the value of 3c.a is equal to _______.
MEDIUM
JEE Main
IMPORTANT

Let ABC be a triangle such that BC=a,CA=b, AB=c,a=62,b=23 and b·c=12

Consider the statements :

S1a×b+c×b-c=622-1

S2: ACB=cos-123. Then

MEDIUM
JEE Main
IMPORTANT
The shortest distance between the lines x+7-6=y-67=z and 7-x2=y-2=z-6 is
MEDIUM
JEE Main
IMPORTANT
Let a=i^-j^+2k^ and let b be a vector such that a×b=2i^-k^ and a·b=3. Then the projection of b on the a-b is:
MEDIUM
JEE Main
IMPORTANT
Let a=αi^+j^-k^ and b=2i^+j^-αk^,α>0. If the projection of a×b on the vector -i^+2j^-2k^ is 30, then α is equal to
HARD
JEE Main
IMPORTANT
The plane passing through the line L:l x-y+31-l z=1,x+2y-z=2 and perpendicular to the plane 3x+2y+z=6 is 3x-8y+7z=4. If θ is the acute angle between the line L and the y-axis, then 415 cos2θ is equal to ______.
MEDIUM
JEE Main
IMPORTANT
Let a=αi^+j^+βk^ and b=3i^-5j^+4k^ be two vectors, such that a×b=-i^+9i^+12k^. Then the projection of b-2a on b+a is equal to
MEDIUM
JEE Main
IMPORTANT
Let a=2i^-j^+5k^ and b=αi^+βj^+2k^. If a×b×i^·k^=232, then b×2j^ is equal to