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.

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  1. jamalkoiyess

    Linear Algebra How Does Linear Algebra Help with Differential Equations?

    Hello PF, I have just finished my first semester in college and did Calc. 3. Now for the spring semester i have to take differential equations and i have been given the advice that linear algebra comes in handy when dealing with DEs. So can anyone recommend a good introduction for linear algebra...
  2. R

    Stuck on expressing a complex number in the form (a+bi)

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  3. T

    Compare these two Linear Algebra courses

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  4. M

    I Is the set {e^x, x^2} linearly independent?

    Hello all. I have a question about linear dependency. Suppose we have a set ##S## of functions defined on ##\mathbb{R}##. ##S = \{e^x, x^2\}##. It seems very intuitive that this set is linear independent. But, we did something in class I'm unsure about. Proof: Let ##\alpha, \beta \in...
  5. BiGyElLoWhAt

    Help with coefficients matrix in spring system

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  6. M

    MHB Finding B^-1 in 3x3 Matrices with Linear Algebra

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  7. Rectifier

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  8. C

    Courses Course suggestion for student interested in Condensed Matter

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  9. M

    I Is Every Isomorphism in Vector Spaces Reflexive?

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  10. Mr Davis 97

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    Homework Statement Let ## \mathbb{V} = \{0 \}## consist of a single vector ##0## and define ##0 + 0 = 0## and ##c0 = 0## for each scalar in ##\mathbb{F}##. Prove that ##\mathbb{V}## is a vector space. Homework EquationsThe Attempt at a Solution Proving that the first six axioms of a vector...
  11. M

    I Proof that every basis has the same cardinality

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  12. M

    Proving Vector Space Property: αa = 0 ⟹ α = 0 or a = 0

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  13. G

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  14. M

    I Linear least-squares method and row multiplication of matrix

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  15. kyphysics

    Linear Algebra Any Great Linear Algebra Books for First-Time Learners?

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  16. R

    Quick question on intro to linear algebra book

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  17. J

    I What's the geometric interpretation of the trace of a matrix

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  18. almarpa

    Algebra Similar book to Kleppner's Quick Caculus for linear algebra

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  19. binbagsss

    QM Bra & Ket Linear Algebra Hermitian operator proof -- quick question

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  20. Mr Davis 97

    I Difference between vectors in physics and abstract vectors

    I am taking a linear algebra course and an introductory physics course simultaneously, so I am curious about the connections between the two when it comes to vectors. In beginning linear algebra, you typically study vectors in ## \Re^{2}## and ## \Re^{3}##. Are these the same vector spaces used...
  21. T

    Linear Algebra, subset of R2 not closed under scalar multipl

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  22. D

    Linear Algebra with Proof by Contradiction

    This is a linear algebra question which I am confused. 1. Homework Statement Prove that "if the union of two subspaces of ##V## is a subspace of ##V##, then one of the subspaces is contained in the other". The Attempt at a Solution Suppose ##U##, ##W## are subspaces of ##V##. ##U \cup W##...
  23. M

    Wrong answer on Linear Algebra and Its Applications 4th Ed.

    Homework Statement The Attempt at a Solution \left[ \begin{array}{cccc} 1 & 0 & 5 & 2 \\ -2 & 1 & -6 & -1 \\ 0 & 2 & 8 & 6 \end{array} \right] \sim \left[ \begin{array}{cccc} 1 & 0 & 5 & 2 \\ 0 & 1 & 4 & 3 \\ 0 & 0 & 0 & 0 \end{array} \right] From the RREF it is...
  24. T

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  25. peasqueeze

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  26. Jeffack

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  27. D

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  28. icesalmon

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  29. F

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  30. R

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  31. Delta what

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  32. M

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  33. J

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  34. M

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  35. M

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  36. M

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  37. DavideGenoa

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  38. kelvin490

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  39. arpon

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  40. B

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  41. Danielm

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  42. Danielm

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  43. S

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  44. odietrich

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  45. S

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  46. D

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  47. ibkev

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  48. Y

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  49. micromass

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  50. smodak

    Linear Algebra Found a real nice free linear algebra book

    https://www.math.ucdavis.edu/~anne/linear_algebra/
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