4. Consider P3 with inner product (p(x), q(x)) = [_ p(x) q(x) dx. (a) [2 pts] Find the cosine of the angle between the vectors a and 3x2 - 2x - 1 in this inner product space. (b) [6 pts] Use Gram-Schmidt to find an orthonormal basis for the space U = span{x, 3x - 2x - 1, 5x + 2x}