4.1.6. Find all possible values of a and b in the inner product (v, w) = a v1 w1 + bu2 w2 that make the vectors (1,2), (-1,1), an orthogonal basis in R2.
4.1.7. Answer Exercise 4.1.6 for the vectors (a) (2,3), (-2,2); (b) (1,4), (2,1).