Question 40
VectorsWhat is the angle between a = (3i − 4j) and b = (6i + 4j)?
- A.130°
- B.87°
- C.100°
- D.110°
Show the answer and explanation
Answer: B (87°)
Explanation
a·b = 18 − 16 = 2, |a| = 5, |b| = √52. cos θ = 2/(5√52) ≈ 0.0555, so θ ≈ 86.8° ≈ 87°.