Question: What is the projection of vector A = 3i + 4j onto vector B = i + j? (2020)
Options:
Correct Answer: 5
Solution:
proj_B(A) = (A · B / |B|^2)B = ((3*1 + 4*1) / (1^2 + 1^2))(i + j) = (7/2)(i + j) = 3.5.