M340L Exam 2B: Linear Algebra - Prof. Arlo W. Schurle, Exams of Mathematics

The second midterm exam for a linear algebra course, focusing on topics such as vector spaces, bases, matrix operations, and solving systems of linear equations. Students are required to explain concepts in detail without using matrices or pivots.

Typology: Exams

Pre 2010

Uploaded on 05/23/2010

koofers-user-dp3
koofers-user-dp3 🇺🇸

10 documents

1 / 6

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
M340L EXAM 2B Your name:
SPRING, 2010
Dr. Schurle Your UTEID:
Show all your work on these pages. Be organized and neat. Your work should be your
own; there should be no talking, reading notes, checking laptops, using cellphones, .. . .
1. (10 points) Suppose that v1,v2,...,vpare vectors in a vector space Vand that H=
Span{v1,v2,...,vp}. Explain in detail how to get a basis for Hthat consists of vectors
from the list v1,v2,...,vp. The vector space Vmay not be any Rq, so you CANNOT
use columns or matrices or pivots in your explanation.
2. (10 points) Suppose His a n×nmatrix and the equation Hx=bis consistent for
every bin Rn. Does the equation Hx=0have a nontrivial solution? Justify your
answer.
pf3
pf4
pf5

Partial preview of the text

Download M340L Exam 2B: Linear Algebra - Prof. Arlo W. Schurle and more Exams Mathematics in PDF only on Docsity!

M340L EXAM 2B Your name: SPRING, 2010 Dr. Schurle Your UTEID:

Show all your work on these pages. Be organized and neat. Your work should be your own; there should be no talking, reading notes, checking laptops, using cellphones,....

  1. (10 points) Suppose that v 1 , v 2 ,... , vp are vectors in a vector space V and that H = Span{v 1 , v 2 ,... , vp}. Explain in detail how to get a basis for H that consists of vectors from the list v 1 , v 2 ,... , vp. The vector space V may not be any Rq, so you CANNOT use columns or matrices or pivots in your explanation.
  2. (10 points) Suppose H is a n × n matrix and the equation Hx = b is consistent for every b in Rn. Does the equation Hx = 0 have a nontrivial solution? Justify your answer.

YOUR SCORE: /

  1. (10 points) Suppose that A is a p × q matrix. Explain in detail why rank A + dim Nul A = q.
  2. (10 points) Let H be the xz-coordinate plane in R^3 , that is, H is the set of all

  

x y z

  

such that y = 0. Is H a subspace of R^3? Justify your answer.

  1. (12 points) Find a basis for the subspace of P 3 spanned by the following polynomials. Show the work that justifies your answer. C

1 − t − t^2 , t + t^2 − 2 t^3 , −2 + 5t + 5t^2 − 6 t^3 , t^2 + t^3 , 4 − 5 t − 2 t^2 + 5t^3

  1. (12 points) A system of eight linear equations in eight unknowns never has a unique solution, regardless of the constants on the right sides of the equations.

(a) Will the system always be consistent, regardless of the constants on the right sides of the equations? Justify your answer.

(b) What can you say about the dimension of the null space of the coefficient matrix of this system? Justify your answer.

C

  1. (12 points) The list of polynomials B = {1 + t + 2t^2 , 1 + 2t + 3t^2 , 2 + 2t + 5t^2 } is a basis for P 2.

(a) Find p(t) when [p(t)]B =

 

 .

(b) Write q(t) = 3 + t + 5t^2 as a linear combination of the basis vectors in B.