#21. Let G be the set of all real 2 x 2 matrices where ad + 0, Prove that under matrix multiplication. Let N = (a) N is a normal subgroup of G. (b) G/N is abelian.
- The set of all 2 x 1 matrices C] where r < 0, with the usual operations in R2.
Let M be the set of 2 x 2 matrices of the form (82) where a, d ER-{0}. Consider the usual matrix multiplication, i.e: ae + bg af +bh ce + dg cf + dh (2)) = (ce ) (a) Show that (M,-) is an abelian group. (b) Compute the cyclic subgroup generated by M = What is the order of M? (6 -4) € M.
2. Let X be a continuous random variable. Let R be the set of all real numbers, let Z be the set of all integers, and let Q be the set of all rational numbers. Please calculate (1) P(X ? R), (2) P(X ? Z), and (3) P(X EQ)
5. Prove or disprove the following statements (a) Let A B and C be 2 x 2 matrices. If AB = AC, then B = C (b) If Bvi,.., Bvh} is a then vi, . ., vk} is a linearly independent set in R". linearly independent set in R* where B is a kx n matrix,
5. Prove or disprove the following statements (a) Let A B and C be 2 x 2 matrices. If AB = AC, then B...
4. Let M be the set of 2 x 2 matrices of the form (62) where a, d E R - {0}. Consider the usual matrix multiplication ·, i.e: ae + bg af + bh ce + dg cf + dh (a) Show that (M,·) is an abelian group. 1 (b) Compute the cyclic subgroup generated by M = What is the order of M? 66 -4) (1) EM EM.
O Q 2 (C) Let S be the set of matrices of the form A= a az ag where a ja, are arbitrary real numbers. Show there exists a unique matrix such that A EA for all A in S.
Let X be a set and let T be the family of subsets U of X such
that X\U (the complement of U) is at most countable, together with
the empty set. a) Prove that T is a topology for X. b) Describe the
convergent sequences in X with respect to this topology. Prove that
if X is uncountable, then there is a subset S of X whose closure
contains points that are not limits of the sequences in S....
3. (a) Show the set of all matrices of the form х A у x + y + z 2 is a subspace of the vectors space M2(R) of all 2 x 2 matrices with entries in R. (b) Find a basis for this subsace and prove that it is a basis. (c) What is the dimension of this subspace?
(2) Let Pn [x] = {p € P[x] : degp <n}, where P[x] is the set of all polynomials. Let the polynomials li() defined by II;tilt - a;) i=0,1,...11 bi(T) = 11: a; - aj) where aj, j = 0,1,..., are distinct real numbers and aia . Show that (d) The change of basis transformation from the standard basis ', j = 0,1,...,n to l; () is given by the Vandermonde matrix (1 00 ... am 1 01 .01 1...