EASY
JEE Main
IMPORTANT
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If the four points, whose position vectors are 3i^-4j^+2k^,i^+2j^-k^,-2i^-j^+3k^   and 5i^-2αj^+4k^ are coplanar, then α is equal to

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Important Questions on Vector Algebra

HARD
JEE Main
IMPORTANT
Let a=-i^-j^+k^,a·b=1 and a×b=i^-j^. Then a-6b is equal to
EASY
JEE Main
IMPORTANT
If the vectors a=λi^+μj^+4k^,b=-2i^+4j^-2k^ and c=2i^+3j^+k^ are coplanar and the projection of a on the vector b is 54 units, then the sum of all possible values of λ+μ is equal to
EASY
JEE Main
IMPORTANT
Let a,b and c be three non-zero non-coplanar vectors. Let the position vectors of four points A, B, C and D be a-b+c,  λa-3b+4c, -a+2b-3c and 2a-4b+6c respectively. If AB, AC and AD are coplanar, then λ is :
HARD
JEE Main
IMPORTANT
If a=i^+2k^, b=i^+j^+k^, c=7i^-3j^+4k^, r×b+b×c=0 and r·a=0 then r.c is equal to:
HARD
JEE Main
IMPORTANT
Let a=4i^+3j^ and b=3i^-4j^+5k^  and c is a vector such that c·(a×b)+25=0,c·(i^+j^+k^)=4 and projection of c on a is 1 , then the projection of c on b equals: 
HARD
JEE Main
IMPORTANT
If a, b, c are three non-zero vectors and n^ is a unit vector perpendicular to c such that a=αb-n^,α0 and  b·c=12, then c×a×b is equal to:
HARD
JEE Main
IMPORTANT

Let λ,a=λi^+2j^-3k^,b=i^-λj^+2k^, If ((a+b)×(a×b))×(a-b)=8i^-40j^-24k^ then |λ(a+b)×(a-b)|2 is equal to

EASY
JEE Main
IMPORTANT
Let aand b be two vectors. Let |a|=1,|b|=4 and a·b=2. If c=(2a×b)-3b, then the value of b·c is