Question: If vector A = 5i + 5j and vector B = 5i - 5j, what is the angle between them?
Options:
Correct Answer: 90 degrees
Solution:
cos(θ) = (A · B) / (|A||B|) = (25 - 25) / (5√2 * 5√2) = 0, θ = 90 degrees.