MA 200 Spring 2024 Exam 1 Review - Practice Problems
1. Find the general solution to
x1 − 3x2 − 9x3 + 5x4 = 0
x2 − 2x3 − x4 = 0
and write it in parametric vector form. What is a geometric description of the solution set?
2. Which of the following sets are linearly independent? Justify/explain your answers.
10 5
(a) −6 , −3
2 1
1 0 3
(b) −2 , 0 , −5
−1 0 4
1 −2 1 0
1 1 −1
, , , 9
(c) 0 3 2 −4
−1 5 3 4
3. Give an example of a matrix which is...
(a) ...in echelon form.
(b) ...in reduced echelon form.
(c) ...is not in echelon form.
1 1
4. Let A = −2 −1 and T : R2 → R3 by T (⃗x) = A · ⃗x.
−1 −3
(a) What is the domain of T , and what is the codomain of T ?
2
(b) For ⃗v = −7, is ⃗v in the range of T ? If so, how many vectors in R2 are there with ⃗v
4
as their image?
5. Provide an argument to explain the following:
“If a set of vectors {v⃗1 , v⃗2 , . . . , v⃗k } in Rn contains more vectors than there are entries in
the vector (i.e., k > n), then the set is linearly dependent.”
3 −5 0
6. Let A = −6 2 4 .
9 −7 −4
(a) Do the columns of A span R3 ? If not, find a vector in R3 which is not in the span of
these vectors.
(b) Do the columns of A form a linearly independent set?
(c) Put A into reduced row echelon form.
2
7. Let v⃗1 = .
−1
(a) Define a vector v⃗2 such that span{v⃗1 , v⃗2 } = R2 . Explain your reasoning/why your
answer works.
(b) Is your set {v⃗1 , v⃗2 } linearly independent, or linearly dependent? Justify your answer.
(c) Define a vector v⃗3 such that span{v⃗1 , v⃗3 } ̸= R2 . Explain your reasoning/why your
answer works.
(d) Is your set {v⃗1 , v⃗3 } linearly independent, or linearly dependent? Justify your answer.
8. Determine whether each statement is True or False. Justify your response.
(a) The echelon form of a matrix A is uniquely determined by A.
(b) The transformation T : R2 → R2 defined by
x1 2x1 + 3x2 − 1
T =
x2 x1 − x2
is a linear transformation.
9. Is the following system consistent or inconsistent? Find a solution if one exists.
2x − 2y = −6
x − y + z=1
3y − 2z = −5
10. Let T : R2 → R2 be the linear transformation given by reflection across the line y = x
followed by projection onto the x-axis. Find the standard matrix of T .