The set {u1,u2,u3} below is an orthogonal basis of R3 (every pair has dot product zero — you can verify this quickly):
u1=(2, 1, 2),u2=(1, 2, −2),u3=(−2, 2, 1)
Note that it is orthogonal, not orthonormal. Write the vector x=(6, 3, −3) in this basis as
x=c1u1+c2u2+c3u3
What is (c1, c2, c3)?