Question 1
Consider the vectors v = 4i - 8k, a = 2i + 2j - k and b = 2i - j + 2k.
a) Find a vector of magnitude v'5in the direction of v.
[6]
b) Find the angle 0 (in radians) that is between a and b.
[6]
c) Find a unit vector that is perpendicular to both vectors a and b.
[8]
Question 2
Let A be a square matrix and let
and
a) Find S+P.
[4)
b) Show that S is symmetric and P is skew-symmetric.
[6)
c) Show that if A is symmetric, then S = A and P = 0.
[4]
Question 3
Consider the matrix B = (
2 ~4 ) .
2 3 -1
a) Use the Cofactor expansion method, expanding along the first row, to evaluate the determi-
nant of B.
[9)
b) Is B invertible? If it is, find B- 1.
[14)
[6]
Question 4
Show that u 1 = (1, 1, 1), u 2 = (1, 2, 3) and u3 = (1, 5, 8) span JR3 (use Gaussian).
[15)
Question 5
a) Prove that in a vector space, the negative of a vector is unique.
[9]
b) Determine whether the following set is a subspace of !Rn.
[13]
1