Exercise 4.4.11

(a) Two orthonormal vectors are $q_1=\frac{1}{10}(1,3,4,5,7)$ and $q_2=\frac{1}{10}(-7,3,4,-5,1)$

(b) Closest projection in the plane $=$ projection $Q{Q}^T(1,0,0,0,0)=(0.5,-0.18,-0.24,0.4,0)$.