Answer: |a||b|.
- A |a||b|
- B 0
- C -|a||b|
- D 1
Correct answer: A. |a||b|
Explanation: cos(0) = 1, so a.b = |a||b| x 1 = |a||b|. Parallel vectors have the maximum positive dot product.
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