Linear algebra is the branch of mathematics concerning linear equations such as:
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1
+
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a
n
x
n
=
b
,
{\displaystyle a_{1}x_{1}+\cdots +a_{n}x_{n}=b,}
linear maps such as:
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x
1
,
…
,
x
n
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↦
a
1
x
1
+
⋯
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a
n
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n
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{\displaystyle (x_{1},\ldots ,x_{n})\mapsto a_{1}x_{1}+\cdots +a_{n}x_{n},}
and their representations in vector spaces and through matrices.Linear algebra is central to almost all areas of mathematics. For instance, linear algebra is fundamental in modern presentations of geometry, including for defining basic objects such as lines, planes and rotations. Also, functional analysis, a branch of mathematical analysis, may be viewed as the application of linear algebra to spaces of functions.
Linear algebra is also used in most sciences and fields of engineering, because it allows modeling many natural phenomena, and computing efficiently with such models. For nonlinear systems, which cannot be modeled with linear algebra, it is often used for dealing with first-order approximations, using the fact that the differential of a multivariate function at a point is the linear map that best approximates the function near that point.
(Not an assigned problem...)
1. Homework Statement
pg 244 of "Mathematical Methods for Physics and Engineering" by Riley and Hobson says that given the following two properties of the inner product
It follows that:
2. Attempt at a solution.
I think that both of these solutions are...
I'm having trouble getting started on this one and I'd really appreciate some hints. This question comes from Macdonald's Linear and Geometric Algebra book that I'm using for self study, problem 2.2.4.
Homework Statement
Let U1 and U2 be subspaces of a vector space V.
Let U be the set of all...
Homework Statement
Find the SVD of
Homework EquationsThe Attempt at a Solution
I'm stuck
My question is why in the solution it originally finds u_2=[1/5,-2/5]' but then says u_2=[1/sqrt(5),-2/sqrt(5)]'. I don't see what math was done in the solution to change the denominator from 5...
I know the arrow -> means a map.
For example, defines a linear map. But I cannot figure out what does a X mean?
I know that above denote a inner product map. whatever is on the left of the : is defined by whatever is on the right. but what is the x symbol? What is the correct way to read...
Homework Statement
Let A be an n×n matrix which has the property that A^2 =A.
(i) Write down the most general polynomial in AHomework EquationsThe Attempt at a Solution
My biggest problem is that I don't even understand what the question is asking
Is it just sum (alphaA^n)=0
but A^n=A...
Homework Statement
Show that the following is NOT a vector space:
{(a, 1) | a, b, c, ∈ ℝ}
{(b, c)
Note: this is is meant to be a 2x2 matrix. This may not have been clear in how I formatted it.
2. The attempt at a solution
I am self-studying linear algebra, and have had a difficulty...
Admit that V is a linear space about \mathbb{R} and that U and W are subspaces of V. Suppose that S: U \rightarrow Y and T: W \rightarrow Y are two linear transformations that satisfy the property:
(\forall x \in U \cap W) S(x)=T(x)
Define a linear transformation F: U+W \rightarrow Y that...
Homework Statement
Let(v1, v2, v3) be three linearly independent vectors in a vector space V. Is the set {v1-v2, v2-v3, v3-v1} linearly dependent or independent?
Homework Equations
Linearly independent is when c1v1+c2v2+...+ckvk=0
and c1=c2=...ck=0
The Attempt at a Solution
c1(v1-v2)+...
Homework Statement
I'm told to find the matrix Q of the matrix A
Homework EquationsThe Attempt at a Solution
So my problem is that in the answer key they have S = (1/3)... and I have no idea where this 1/3 comes from. I get an equivalent answer for X_1, X_2, and X_3
S = [X_1, X_2, X_3] but...
which has higher failure rate: linear algebra or intro to programming. I understand failure rate might be skewed: math majors, who are gifted and interested in math, are required to take linear algebra but not intro to programming, while CS majors are required to take both. Which class do CS...
Hello everyone, I have a question. I'm not sure if it is trivial. Does anyone have ideas of finding a matrix ##A\in M_n(\mathbb{C})##, where ##A## is normal but not self-adjoint, that is, ##A^*A=AA^*## but ##A\neq A^*?##
Homework Statement
The cylinder x^2 + y^2 = 1 intersects the plane x + z = 1 in an ellipse. Find the point on the ellipse furthest from the origin.
Homework Equations
$f(x) = x^2 + y^2 + z^2$
$h(x) = x^2 + y^2 = 1$
$g(x) = x + z = 1$
The Attempt at a Solution
$\langle 2x, 2y, 2z \rangle...
Homework Statement
Let R2 have the Euclidean inner product and use the Gram-Schmidt process to transform the basis {u1,u2} into an orthonormal basis.
u1 = (1,-3)
u2 = (2,2)
Homework Equations
Gram-Schmidt process:
\\v_1 = u_1
\\v_2= u_2 -
\frac{\left ( \left \langle u_2, v_1\right \rangle...
Homework Statement
I'm trying to solve this circuit
when I try to simulate and run a dc sweep i get that it can't be solved. When I try to find the answer using linear algebra
I get this answer after I throw it into MATLAB with the warning
“[w]arning: Matrix is close to singular or...
Homework Statement
Virtually all quantum mechanical calculations involving the harmonic oscillator can be done in terms of the creation and destruction operators and by satisfying the commutation relation \left[a,a^{\dagger}\right] = 1
(A) Compute the similarity transformation...
Homework Statement
I feel like I should know the answer to this, so I believe this to be an easy question. Say have matrix A, and I store the elimination matrices E_1,1 E_2,1 etc. and somewhere in the elimination process I have to use a permutation matrix to swap rows. My question is when I...
Suppose ##x_1(t)## and ##x_2(t)## are two linearly independent solutions of the equations:
##x'_1(t) = 3x_1(t) + 2x_2(t)## and ##x'_2(t) = x_1(t) + 2x_2(t)##
where ##x'_1(t)\text{ and }x'_2(t)## denote the first derivative of functions ##x_1(t)## and ##x_2(t)##
respectively with respect to...
Homework Statement
So I think I found an error in the solution were it attempts to find q_2^
I'm asked find the orthornomal basis for the column space of matrix A.
Homework EquationsThe Attempt at a Solution
[/B]
My question is in what it puts for q_2^
A_2 = [4/3 4/3 -2/3]^T
||A_2|| =...
My professor states that "A matrix is diagonalizable if and only if the sum of the geometric multiplicities of the eigen values equals the size of the matrix". I have to prove this and proofs are my biggest weakness; but, I understand that geometric multiplicites means the dimensions of the...
Homework Statement
I feel like this is a easy question but it seems the answer key doesn't seem to be right.
So say I have 2 vectors
and I'm trying to find the projection of vector u perpendicular to the vector v
Homework EquationsThe Attempt at a Solution
So I don't remember doing...
Homework Statement
I ask for help in solving the exercises in this project on applied linear algebra. The problem outlined in the project is one in which we are tasked with modeling the demise of a gambler.
I need help solving exercise 1 (in red) on page 6. I have pasted the exercise text...
Homework Statement
So yeah I'm doing a project were I get to create a problem. I would like to learn how to solve a AC RLC circuit using linear algebra. I'm trying to find all of the currents on the edges of the graphs and find all of the voltages at the nodes connecting the edges. I don't...
micromass submitted a new PF Insights post
In High School and Want to Do Advanced Mathematics?
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I'll try to be concise. I've been out of math for years and never truly learned to understand it. Until now. I want to put the growth mindset theory to the test and see if I can handle physics (or any STEM field) on a university difficulty. To verify if I'm up to it and even have the slightest...
Homework Statement
Let A be an n x n matrix, and let v, w ∈ ℂn.
Prove that Av ⋅ w = v ⋅ A†w
Homework Equations
† = conjugate transpose
⋅ = dot product
* = conjugate
T = transpose
(AB)-1 = B-1A-1
(AB)-1 = BTAT
(AB)* = A*B*
A† = (AT)*
Definitions of Unitary and Hermitian Matrices
Complex Mod...
So I was trying to learn how to find the angle between two complex 4-dimentional vectors. I came across this paper, http://arxiv.org/pdf/math/9904077.pdf which I found to be a little confusing and as a result not overly helpful. I was wondering if anyone could help at all?
Many thanks in...
Homework Statement
For each matrix A, I need to find a basis for each generalized eigenspace of ## L_A ## consisting of a union of disjoint cycles of generalized eigenvectors. Then I need to find the Jordan canonical form of A.
The matrices are:
## a)
\begin{pmatrix}
1 & 1\\
-1 & 3...
Hey,
(I have already asked the question at http://physics.stackexchange.com/questions/244586/bloch-sphere-interpretation-of-rotations, I am not sure this forum's etiquette allows that!)
I am trying to understand the following statement. "Suppose a single qubit has a state represented by the...
Homework Statement
Given an nxn matrix, if a b exists so Ax=b has no solutions, can A be one-to-one?
Homework Equations
I understand that as a linear transformation, you need things such as (to be one-to-one as a linear trans)
1. n pivots
2. Only the trivial solution exists to Ax=0
Ax=b...
Hey,
I need help with part D2. My explanation is not right so I honestly do not know what I am suppose to write. My assignment is attached to this thread.
Hello all!
I've just started to study general relativity and I'm a bit confused about dual basis vectors.
If we have a vector space \textbf{V} and a basis \{\textbf{e}_i\}, I can define a dual basis \{\omega^i\} in \textbf{V}^* such that: \omega^i(\textbf{e}_j) = \delta^i_j But in some pdf and...
Homework Statement
Derive Cholesky Decomposition for a 3x3 matrix
Homework Equations
IN: S is Real matrix with dimensions 3x3 and is Symmetric and semi-definite
Out: L is a Real matrix with dimensions 3x3 such that
S=L*L^t
L is lower-triangular
The Attempt at a Solution
We learned this in...
Homework Statement
Does the line through the point P(1, 2, 3) with direction vector d = (1, 2, -3) lie in the plane 2x+y-z=3?
Homework EquationsThe Attempt at a Solution
From the 2x+y-z i can get the vector (2, 1, -3) and the direction vector, their dot product does not equal zero. So, no it...
Homework Statement
Solve the linear system of equations:
ax+by+z=1
x+aby+z=b
x+by+az=1
for a,b\in\mathbb R
and plot equations and solutions in cases where the system is consistent.
Homework Equations
-Cramer's rule
-Kronecker-Capelli's theorem
The Attempt at a Solution
Using Cramer's rule, we...
Homework Statement
Plot the solution set of linear equations
x-y+2z-t=1
2x-3y-z+t=-1
x+7z=8
and check if the set is a vector space.
2. The attempt at a solution
Augmented matrix of the system:
\begin{bmatrix}
1 & -1 & 2 & -1 & 1 \\
2 & -3 & -1 & 1 & -1 \\
1 & 0 & 7 & 0 & 8 \\...
Homework Statement
Prove that, if ##T,S\in \mathcal{L}(V)## then ##TS## and ##ST## have the same eigenvalues.
Homework EquationsThe Attempt at a Solution
Suppose ##T## is written in a basis in which its matrix is upper triangular, and so is ##S## (these bases may be of different list of...
Homework Statement
For the system of springs
a) Assemble the stiffness matrix K and the force-displacement relations, K*u = f
b) Find the L*D*L^T factorization of K. Use Matlab to solve
c) Use the boundary conditions and applied forces to find the displacements
Homework EquationsThe Attempt...
Homework Statement
I am given the follow graph and asked to find the left null space
Homework EquationsThe Attempt at a Solution
First I start by transpose A because I know that the left null space is the null space of the incidence matrix transposed. I then reduce it to reduce row echelon...
Homework Statement
The question asks to show whether the following are sub-spaces of R^3. Here is the first problem. I want to make sure I'm on the right track.
Problem: Show that W = {(x,y,z) : x,y,z ∈ ℝ; x = y + z} is a subspace of R^3.
Homework Equations
None
The Attempt at a Solution...
During lecture, the professor gave us a theorem he wants us to prove on our own before he goes over the theorem in lecture.
Theorem: Let ##V_1, V_2, ... V_n## be subspaces of a vector space ##V##. Then the following statements are equivalent.
##W=\sum V_i## is a direct sum.
Decomposition of...
Homework Statement
Hey, I posted another question yesterday, and thanks to the kindness and brilliance of hall of ivy, I was able to solve it. However when I apply the same logic to this new question I cannot seem to get it, can someone explain or show me how to do this question.
Consider the...
Homework Statement
Let U is the set of all polynomials u on field \mathbb F such that u(3)=u(-2)=0. Check if U is the subspace of the set of all polynomials P(x) on \mathbb F and if it is, determine the set W such that P(x)=U\oplus W.
Homework Equations
-Polynomial vector spaces
-Subspaces...
Homework Statement
Consider the linear transformation T from
V = P2
to
W = P2
given by
T(a0 + a1t + a2t2) = (−4a0 + 2a1 + 3a2) + (2a0 + 3a1 + 3a2)t + (−2a0 + 4a1 + 3a2)t^2
Let E = (e1, e2, e3) be the ordered basis in P2 given by
e1(t) = 1, e2(t) = t, e3(t) = t^2
Find the coordinate matrix...
Homework Statement
Prove that \dim L(\mathbb F)+\dim Ker L=\dim(\mathbb F+Ker L) for every subspace \mathbb{F} and every linear transformation L of a vector space V of a finite dimension.
Homework Equations
-Fundamental subspaces
-Vector spaces
The Attempt at a Solution
Theorem: [/B]If...
Homework Statement
Find all values a\in\mathbb{R} such that vector space V=P_2(x) is the sum of eigenvectors of linear transformation L: V\rightarrow V defined as L(u)(x)=(4+x)u(0)+(x-2)u'(x)+(1+3x+ax^2)u''(x). P_2(x) is the space of polynomials of order 2.
Homework Equations
-Eigenvalues and...
Homework Statement
Determine whether the set spans ℜ3. If the set does not span ℜ3 give a geometric description of the subspace it does span.
s = {(1, 0, 3), (2, 0, -1), (4, 0, 5), (2, 0, 6)}
Homework EquationsThe Attempt at a Solution
I am having trouble with the second part of this problem...
I'm looking for an excellent introductory linear algebra textbook for my second year pure mathematics course. My lecturer highly recommended Introduction to Linear Algebra by Marcus and Minc. She said she has searched for it for many years without success, as it is out of print. I love classic...