Let A be an m x n matrix and b and x be vectors such that
Ab=x.
a) What vector space is x in?
b) What vector space is b in?
c) Show that x is a linear combination of the columns of A.
d) Let x' be a linear combination of the columns of A. Show that
there is a vector b' so that Ab' = x'.
Let A be a diagonalizable n × n matrix and let P be an
invertible n × n matrix such that B = P−1AP is the diagonal form of
A. Prove that Ak = PBkP−1, where k is a positive integer. Use the
result above to find the indicated power of A. A = 6 0 −4 7 −1 −4 6
0 −4 , A5 A5 =
Let A be a diagonalizable n × n
matrix and let P be an invertible n × n
matrix such that
B = P−1AP
is the diagonal form of A. Prove that
Ak = PBkP−1,
where k is a positive integer.
Use the result above to find A5
A =
4
0
−4
5
−1
−4
6
0
−6
Let A be an m x n matrix. Prove that
Ax = b has at least one solution
for any b if and only if A has linearly
independent rows.
Let V be a vector space with dimension 3, and let
V = span(u, v,
w). Prove that u,
v, w are linearly independent (in
other words, you are being asked to show that u,
v, w form a basis for
V)
Let A be a m × n matrix with entries in R. Recall that the row
rank of A means the dimension of the subspace in RN
spanned by the rows of A (viewed as vectors in Rn), and
the column rank means that of the subspace in Rm spanned
by the columns of A (viewed as vectors in Rm).
(a) Prove that
n = (column rank of A) + dim S,
where the set S is the solution space...
Suppose C is a m × n matrix and A is a n × m matrix. Assume CA =
Im (Im is the m × m identity matrix). Consider the n × m system Ax
= b.
1. Show that if this system is consistent then the solution is
unique.
2. If C = [0 ?5 1
3 0 ?1]
and A = [2 ?3
1 ?2
6 10] ,,
find x (if it exists) when
(a) b =[1...
A m*n matrix A. P is the dimension of null space of A. What are
the number of solutions to Ax=b in these cases. Prove your
answer.
a. m=6, n=8, p=2
b. m=6, n=10, p=5
c. m=8, n=6, p=0
Let v1 be an eigenvector of an n×n matrix A corresponding to λ1,
and let v2, v3 be two linearly independent eigenvectors of A
corresponding to λ2, where λ1 is not equal to λ2. Show that v1, v2,
v3 are linearly independent.
Let A be some m*n matrix. Consider the set S = {z : Az = 0}.
First show that this is a vector space. Now show that n = p+q where
p = rank(A) and q = dim(S). Here is how to do it. Let the vectors
x1, . . . , xp be such that Ax1, .
. . ,Axp form a basis of the column space of A (thus
each x can be chosen to be some unit...
7. Let n ∈ N with n > 1 and let P be the set of polynomials
with coefficients in R.
(a) We define a relation, T, on P as follows: Let f, g ∈ P. Then
we say f T g if f −g = c for some c ∈ R. Show that T is an
equivalence relation on P.
(b) Let R be the set of equivalence classes of P and let F : R →
P be...