What is Linear algebra: Definition and 999 Discussions

Linear algebra is the branch of mathematics concerning linear equations such as:





a

1



x

1


+

+

a

n



x

n


=
b
,


{\displaystyle a_{1}x_{1}+\cdots +a_{n}x_{n}=b,}
linear maps such as:




(

x

1


,

,

x

n


)


a

1



x

1


+

+

a

n



x

n


,


{\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.

View More On Wikipedia.org
  1. A

    Can anybody check my answers (linear algebra)?

    Homework Statement Let A \in M_n(F) and v \in F^n . Also...[g \in F[x] : g(A)(v)=0] = Ann_A (v) is an ideal in F[x], called the annihilator of v with respect to A. We know that g \in Ann_A(v) if and only if f divides g in F[x]. f is the monic polynomial of lowest degree in the...
  2. K

    Graduate Engineering - Linear Algebra (Graham Schmidt + more)

    Homework Statement No idea how to solve this using graham schmidt. I know how to do graham schmidt and how to solve this problem if I didn't have to use graham schmidt, but I have no idea where to start in order to get my vectors to add to V Found c to be 87 by using vector...
  3. P

    LINEAR ALGEBRA: How to prove system has one unique solution

    Homework Statement Show that the system ∑ hereunder admits one unique solution ∑ = \left[\begin{array}{cc} 1 & a_{1} & a_{1}{}^{2} & a_{1}{}^{3} & | & b_{1}\\ 1 & a_{2} & a_{2}{}^{2} & a_{2}{}^{3} & | & b_{2}\\ 1 & a_{3} & a_{3}{}^{2} & a_{3}{}^{3} & | & b_{3}\\ 1 & a_{4} & a_{4}{}^{2} &...
  4. D

    Linear Algebra (Sparse Matrix and Diff. Eq)

    Homework Statement Homework Equations Not sure. The Attempt at a Solution Have no idea, as I don't have any/much previous experience with Linear Algebra. Can anyone help me with starting on this, hints/tips?
  5. A

    Questions about Linear Algebra

    Homework Statement Let A \in M_n(F) and v \in F^b . Also...[g \in F[x] : g(A)(v)=0] = Ann_A (v) is an ideal in F[x], called the annihilator of v with respect to A. We know that g \in Ann_A(v) if and only if f|g in F[x]. Let V = Span(v, Av, A^2v, ... , A^{k-1}v).. V is teh smallest...
  6. S

    Finding an equation of the plane (Linear Algebra)

    Homework Statement Find an equation of the plane that has y-intercept -5 and is parallel to the plane containing the points P(3, -1, 2), Q(0, 2, 1) and R(5, 2, 0)Homework Equations ax + by + cz + d = 0 The Attempt at a Solution I got two directional vectors u = PQ = (-3, 3, -1) v = PR = (2...
  7. H

    Coding Theory. It also combine some linear algebra as well.

    Hi Guys I just got some problem about coding theory and I don't quite understand what question 2 is asking. Can you guys help me? Thanks a lot.
  8. A

    A question about linear algebra

    Homework Statement Let A \in M_n(F) and v \in F^n. Let k be the smallest positive integer such that v, Av, A^2v, ..., A^kv are linearly dependent. a) Show that we can find a_0, ... , a_{k-1} \in F wiht a_0v + a_1Av + ... + a_{k-1}A^{k-1}v + A^kv = 0 (note that teh coefficient of...
  9. B

    When are linear combinations equal?

    Homework Statement True or False: The linear combinations a_{1}v_{1} + a_{2}v_{2} and b_{1}v_{1} + b_{2}v_{2} can only be equal if a_{1} = b_{1} and a_{2} = b_{2} Homework Equations The Attempt at a Solution I have determined that this statement is false if at least of the...
  10. T

    Linear Algebra subspaces and spans

    Homework Statement Let E = {“ax+by+cz = d” | a; b; c; d ∈ R} be the set of linear equations with real coefficients in the variables x, y and z. Equip E with the usual operations on equations that you learned in high school. addition of equations, denoted below by “⊕” and multiplication by...
  11. S

    Linear algebra problem involving image spaces

    Homework Statement A is a mxn. V is nxn and invertible. Show that imA=imAV2. The attempt at a solution Up until now I haven't done much in the way of proving things. In this case is it enough to show that they are each closed under addition and scalar multiplication? Would that mean that imA is...
  12. A

    Reading Source fr Numerical Linear Algebra?

    I am using An Introduction to numerical linear algebra by Charles Cullen and I'm not very satisfied with it. Kindly suggest me some alternatives. Also suggest good linear algebra book to clear up basics. finally also suggest any online study materials, lecture notes, videos regarding the...
  13. M

    Linear Algebra: Span, Linear Independence Proof

    Homework Statement Suppose v_1,v_2,v_3,...v_n are vectors such that v_1 does not equal the zero vector and v_2 not in span{v_1}, v_3 not in span{v_1,v_2}, v_n not in span{v_1,v_2,...v_(n-1)} show that v_1,v_2,v_3,...,V_n are linearly independent. Homework Equations linear independence...
  14. L

    How to Minimize Error in Elliptical Orbit Model using Linear Algebra

    Linear Algebra Homework help! Homework Statement Suppose a particular object is modeled as moving in an elliptical orbit centered at the origin. Its nominal trajectory is described in rectangular coordinates (r;s) by the constraint equation x1r^2 +x2s^2 +x3rs = 1, where x1; x2; and x3 are...
  15. A

    A question about linear algebra (change of basis of a linear transformation)

    Homework Statement Let A \in M_n(F) and v \in F^n. Let v, Av, A^2v, ... , A^{k-1}v be a basis, B, of V. Let T:V \rightarrow V be induced by multiplication by A:T(w) = Aw for w in V. Find [T]_B, the matrix of T with respect to B. Thanks in advance Homework Equations...
  16. estro

    Linear Algebra - orthogonal vector fields

    I want to prove that: Ker(T*)=[Im(T)]^\bot Everything is in finite dimensions. What I'm trying: Let v be some vector in ImT, so there is v' so that Tv'=v. Let u be some vector in KerT*, so T*u=0. So now: <u,v>=<u,Tv'>=<T*u,v'>=0 so every vector in ImT is perpendicular to every vector...
  17. 1

    Vector Space-Spanning Linear Algebra

    Homework Statement Bonus] Let E = {“ax+by+cz = d” | a; b; c; d ∈ R} be the set of linear equations with real coefficients in the variables x, y and z. Equip E with the usual operations on equations that you learned in high school: addition of equations, denoted here by “⊕” and...
  18. 1

    Subspaces of Functions- Linear Algebra

    Homework Statement Which of the following are subspaces of F[R] = {f |f:R-->R}? a) U = {f e F[R]|f(-1)f(1)=0 b) V = " |f(1)+f(2)=0 c) S = " |f(x)=f(-x) d) T = " |f(1)<= 0 Homework Equations The Attempt at a Solution I got S and V or c) and b), is that correct? I...
  19. Z

    Coordinate Transformation in Special Relativity with Linear Algebra Part A

    Homework Statement In the figure, let S be an inertial frame and let S' be another frame that is boosted with speed v along its x'-axis w.r.t. S, as shown. The frames are pictured at time t = t0 = 0: A) Find the Non-relativistic transformation (Galilean Transformation) between the two...
  20. 1

    Polynomial Span related problem Linear Algebra

    Homework Statement Consider the vector space F(R) = {f | f : R → R}, with the standard operations. Recall that the zero of F(R) is the function that has the value 0 for all x ∈ R: Let U = {f ∈ F(R) | f(1) = f(−1)} be the subspace of functions which have the same value at x = −1 and x = 1...
  21. B

    Linear Algebra- Matrix Linear Transformation

    Homework Statement Find the Matrix M which represents the reflection about the line L given by the equation y=(1/2)x. By two methods: a) By writing the composition as a composition of rotations and reflections about the x-axis. Note that the line L makes an angle of pi/6 with the x-axis...
  22. 1

    Polynomial Span and Subspace - Linear Algebra

    Homework Statement Consider the vector space F(R) = {f | f : R → R}, with the standard operations. Recall that the zero of F(R) is the function that has the value 0 for all x ∈ R: Let U = {f ∈ F(R) | f(1) = f(−1)} be the subspace of functions which have the same value at x = −1 and x = 1...
  23. I

    Can (I+A)^-1 be simplified to I+A/2 in linear algebra?

    A is a square matrix n*n with the following properties: A*A=A and A not equal I (identity matrix). How to prove the following equation: (I+A)^-1=I+A/2 ?
  24. A

    What is your best second books for linear algebra?

    Hi, Everyone It is difficult to find nice workable books for more advanced linear algebra. There are numerous publications and internet materials, few of them are workable to me. Interested topics: unitary and Hermitian matrices, Jordan (canonical) form, tridiagonal matrix, Sylvester...
  25. C

    Abstract Linear Algebra, Linear Functional

    Homework Statement problem didn't state, but I assume let V be a vector space: V = C^3 and scalar is C Homework Equations Define a non-zero linear functional T on C^3 such that T ((1, 1, 1)) = T ((1, 1, −1)) = 0 The Attempt at a Solution So let X1 = (1, 1, 1); X2 = (1, 1, -1); It...
  26. S

    What topics are covered in linear algebra class?

    What topics/chapters are covered in a typical linear algebra class? I am a physics/math major but I won't be able to take classes for a few years. I am trying to teach myself linear algebra so I can read physics textbooks. Thanks
  27. S

    Linear Algebra - finding matrix A

    Homework Statement Find A if (2A-1 - 3I)T = 2* \begin{pmatrix} -1 & 2\\ 5 & 4 \end{pmatrix} Homework Equations The Attempt at a Solution I have no idea if I'm even on the right track of solving this question... I simplified the right hand side down to \begin{pmatrix} -2 & 4\\ 10 & 8...
  28. T

    Linear algebra problem (standard matrix for a linear operator)

    Homework Statement Determine the standard matrix for the linear operator defined by the formula below: T(x, y, z) = (x-y, y+2z, 2x+y+z) Homework Equations The Attempt at a Solution No idea
  29. C

    Linear Algebra - Eigenvalue Problem

    Homework Statement Let there be 3 vectors that span a space: { |a>, |b>, |c> } and let n be a complex number. If the operator A has the properties: A|a> = n|b> A|b> = 3|a> A|c> = (4i+7)|c> What is A in terms of a square matrix? Homework Equations det(A-Iλ)=0 The Attempt...
  30. C

    Linear Algebra Proof - Determinants and Traces

    Homework Statement Prove for an operator A that det(e^A) = e^(Tr(A)) Homework Equations The Attempt at a Solution I have no idea how to start. Can someone give me a hint? In general the operator A represented by a square matrix, has a trace Tr(A) = Ʃ A (nn) where A (nn) is...
  31. B

    How Many Bills of Each Denomination Make $100 from 32 Bills?

    Homework Statement I have 32 bills in my wallet in the denominations $1, $5, and $10, worth $100 in total. How many of each denomination do I have? Homework Equations A= # $1 bills B= # $5 bills C= # $10 bills A+B+C = 32 1A+5B+10C = 100 The Attempt at a Solution So I...
  32. N

    Proofing Linear Algebra: Tips, Advice and Pointers

    I have done some "proofs" before in calculus. At this moment I am required to write proofs for linear algebra and I find them highly unintuitive and confusing -- I often don't know where to begin or what to do. Can you guys leave some pointers, tips, advice, etc. for how to prove things...
  33. C

    Linear algebra unique solutions

    This is just a general question. When a coefficient matrix for a linear system has a determinant equal to 0. That means the coefficient matrix does not have an inverse, thus the system does not have a unique solution. Is the above statement correct? What exact is a unique solution? Is...
  34. C

    Proving d(A^-1)/dL = -(A^-1)(dA/dL)(A^-1)

    Homework Statement L = lambda. Prove: d(A^-1)/dL = -(A^-1)(dA/dL)(A^-1) Homework Equations ? The Attempt at a Solution I did this as an analogy with function of numbers, but don't know how to extend this to matricies. for example: lets say A = f(L) d(f(L)^-1)/dL = -...
  35. R

    Does the Vector Space Axiom Hold for V with Given Conditions?

    let V be the collection of the 2*3 matrices with a real entries such that V={[a11 a12 a13 : a21 a22 a23] | a11+a23 =1} determine whether the following vector space axioms holds (a) for all α ε V there exists (-α) such that α + (-α)=0(vector)
  36. S

    Need help understanding Linear algebra proofs (and linear algebra in general)

    Hey all, I am trying to get a head start on Linear Algebra before i start taking classes in a couple weeks. I am about to go into my second year undergraduate and all i have behind my belt is calculus (single varialbe, multivariable, and vector analysis (curl, divergence, etc)). I am...
  37. Y

    Understanding Linear Algebra: Span of Vectors in R^4 Explained

    [b]1. i am given a matrix A= 1 0 2 1 1 1 3 1 2 3 8 -2 -3 3 -5 1 and then it asks why do I know that span {a1, a2, a3, a4} are a subset of R^4. Homework Equations The Attempt at a Solution Is it as easy as saying "because there 4 vectors?"
  38. D

    Matrix, Vector Proof Help for Multivariable Mathematics (Linear Algebra) Course

    Homework Statement Problem 1: If A is an m x n matrix and Ax = 0 for all x ε ℝ^n, prove that A = O. If A and B are m x n matrices and Ax = Bx for all x ε ℝ^n, prove that A = B. (O is the 0 matrix, x is the vector x, and 0 is the 0 vector.)2. The attempt at a solution First off, I understand...
  39. O

    [Linear Algebra] For which a is 0 an eigenvalue?

    Homework Statement I have to find for which "a" an eigenvalue for the following system is 0. The system: 1 -1 1 -1 2 -2 0 a 1 Homework Equations My characterstic equation: (1-λ)(2-λ)(1-λ)+2a -(1-λ) -a = 0The Attempt at a Solution I then proceed: (1-λ)(λ2-3λ-2+a) = 0 but then I'm kind...
  40. S

    Linear Algebra for Quantum Mechanics Prerequisite

    I was going through Linear Algebra which is recommended as a prerequisite to Quantum Mechanics. The topic of LA is vast and deep. So I wanted to know which (specific) topics of LA should be covered as a prerequisite to QM.
  41. T

    Is honors linear algebra worth it?

    Hey everyone, I'm majoring in physics and will be starting my first year in the fall. I'm currently registered in honors linear algebra, but have been thinking that it might be beneficial to take the regular linear algebra course. I'm also in honors calculus, but I know I want to stay in that. I...
  42. C

    Are Planes Passing Through the Origin Vector Spaces or Subspaces?

    Homework Statement Is a set of n-tuples which must respect the conditions of closure under addition and closure under scalar multiplication a vector space or a vector subspace? That is, in a 3-dimensional space, are planes which pass by the origin considered to be subspaces of the 3-dimensinal...
  43. caffeinemachine

    MHB Linear algebra. Rank. linear independence.

    Let $V$ be a finite dimensional vector space. Let $T$ be a linear transformation on $V$ with eigenvalue $0$. A vector $v \in V$ is said to have rank $r > 0$ w.r.t eigenvalue $0$ if $T^rv=0$ but $T^{r-1}v\neq 0$. Let $x,y \in V$ be linearly independent and have ranks $r_1$ and $r_2$ w.r.t...
  44. K

    Abstract Algebra vs Linear Algebra

    Hey guys, As of now, I am in a sets and logic proof based course (Intro to proof-writing). This course basically teaches logic, how to write proofs using examples of algebraic equations, sets: power sets, unions and intersections of classes, etc. With a C in this course, you can register...
  45. M

    Linear algebra - Diagonalization

    does someone know how to solve the following? Homework Statement "Find all matrices A so I A 0 I is Diagonalizable " this is a picture of the matrice http://i46.tinypic.com/258v514.jpg How can I find A?
  46. E

    Linear algebra question, quadratic forms.

    A is a square matrix. x, b are vectors. I know for Ax=b, that given b, there are an infinite number of pairs (A, x) which satisfy the equation. I'm wondering if the same is true for xAx=b. in particular, what if (x, A, b) are all stochastic vectors/matrices (i.e the entries of b and x add to...
  47. J

    Linear Algebra - Matrix Symitry

    Homework Statement A matrix A is skew-symmetric if AT = -A. Write the matrix B below as the sum of a symmetric matrix and a skew-symmetric matrix. B = a b c d e f g h i The Attempt at a Solution So I'm Pretty sure that the Symetric Matrix = B + BT Skew Symetric Martix = B - BT...
  48. T

    Dumb question about this linear algebra equation

    Homework Statement Show that any vector V in a plane can be written as a linear combination of two non-parallel vectors A and B in the plane; that is, find a and b so that V = aA + bB. Take components perpendicular to the plane to show that a = (B x V)\bulletn / (B x A)\bulletn Homework...
Back
Top