EASY
12th CBSE
IMPORTANT
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Using vectors, prove that the parallelogram on the same base and between the same parallels are equal in area.

Important Questions on Vector Algebra

EASY
12th CBSE
IMPORTANT
Prove that in any triangle ABC, cos A=b2+c2-a22bc, where a, b, c are the magnitudes of the sides opposite to the vertices A, B, C, respectively.
MEDIUM
12th CBSE
IMPORTANT
If a, b, c determine the vertices of a triangle, show that  12[b×c+c×a+a×b] gives the vector area of the triangle. Hence deduce the condition that the three points a ,b, c are collinear. Also find the unit vector normal to the plane of the triangle.
MEDIUM
12th CBSE
IMPORTANT
Area of the parallelogram whose diagonals are given by a and b is |a×b|m. Also the area of the parallelogram whose diagonals are 2i-j^+k^ and i-3j^+k^ is 12n square units. Find the value of m+n?
MEDIUM
12th CBSE
IMPORTANT
If a=i^+j^+k^ and b=j^-k^, magnitude of a vector c is xy such that a×c=b and a.c=3, find x.
EASY
12th CBSE
IMPORTANT
The vector in the direction of the vector i^-2j^+2k^ that has magnitude 9 is
EASY
12th CBSE
IMPORTANT
The position vector of the point which divides the join of points 2a-3b and a+b in the ratio 3:1 is
EASY
12th CBSE
IMPORTANT
The vector having initial and terminal points as (2,5,0) and (-3,7,4) respectively is
EASY
12th CBSE
IMPORTANT
The angle between two vectors a and b of magnitudes 3 and 4 respectively and a·b=23 is