Problem 2 2.2, Exercise 5. Find the cosine ef the angle between the normal vectors to the planes 212y+z=14 and 3+y23=l. Problem 3 In Exercises 1 - 3 determine whether the given matrix is in reduced echelon form. 1 0 2 O $2.3, Exercise 2. 0 1 4 O OProblem 4 In Exercises 4 6 we list the reduced echelon form of an augmented matrix of a system of linear equations. 1Winch columns in these augmented matrices contain pivots? Describe all solutions to these systems of equations in the form of (2.3.14). 1 2 [l O i] 2.3, Exercise 5. U 0 1 l U . 0 0 0 1 Problem 8 $2.3, Exercise 7. Suppose that A = [A|b] is the augmented matrix of a system of 4 linear equations in 7 unknowns. Suppose that the solution is defined by 5 parameters. Let E be the 4 x 8 reduced echelon form of A. How many pivots does E have