Texts: Linear Algebra. Please answer ASAP. Will rate.
Problem 9. (5 points) Determine whether the following statements are true or false. All vectors are in ℝ.
1. Every orthogonal set in ℝ^n is a linearly independent set.
2. If a set S = {u1, u2, ..., un} has the property that u_i · u_j = 0 whenever i ≠j, then S is an orthonormal set.
3. A square matrix with orthonormal columns is invertible.
4. If Q is an m Ă— n matrix with orthonormal columns, then Q^TQ = I, the n Ă— n identity matrix.
Note: You can earn partial credit on this problem.