Answer: 5/2.
- A 2
- B 5/2
- C −5/2
- D 5
Correct answer: B. 5/2
Explanation: Dot product = 2 − 2λ + 3 = 0 gives λ = 5/2.
Triangle law of vector addition: placing vector b at the head of vector a, the diagonal from the start to the final head gives the resultant a + b.
Concept context
Vectors, dot product, cross product, and geometric applications