1. Find the rank of matrix A.
A=[1 1 1]
2 3 -1
1 -1 3
3. Find the inverse by Gauss-Jordan (or state that it does not exist) of the matrix in Exercise 1.
4. Find the components and the length of the vector u with initial point P(1, 1, -3) and terminal point Q(-2, -1, 4). Sketch u and determine the unit vector in the direction of u.
5. Consider the vectors a=(-1, 2, -2) and b=(2, 1, -5). Find a · b, the angle between a+b and a-b, and |(a+b)x(-b)|.