1) 0 2) 1 3) a × b 4) b × a Answer: (1) 0 Solution: Given, (2a + 3b) × (5a + 7b) + a × b = 2a x (5a+7b) + 3b x (5a + 7b) + a x b = 10 (a... View Article
1) a . b 2) 1 3) 0 4) ½ Answer: (4) ½ Solution: We can write; (a x b)2 = (a x b).(a x b) = (|a| |b| sin θ). (|a| |b| sin θ) = |a|2.|b|2... View Article
1) 5 2) 1 3) 6 4) 8 Answer: (3) 6 Solution: Suppose, A, B and C are the position vectors of vertices 0, a+b and a-b. As we know, Area of... View Article
1) 6 (b × c) 2) 3 (b × c) 3) 2 (b × c) 4) 0 Answer: (1) 6 (b × c) Solution: Given, (a + 2b + 3c) = 0 a x b + 2b x b + 3c x b = 0 a x b +... View Article
1) π/3 2) π/2 3) π/4 4) π/6 5) 0 Answer: (1) π/3 Solution: Given, projection of the vector a on b is |a × b| So, |a x b| = a.( b/|b|) And... View Article
1) 0 2) tan-1x 3) π/4 4) π/2 Answer: (3) π/4 Solution: Let cosec-1(√41/4) = A cosec A = √41/4 sin A = 4/√41 Using the identity... View Article