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4.1 Vector and Matrix Operations

2 min readjuly 25, 2024

Vector operations are the building blocks of linear algebra. They allow us to manipulate and analyze multidimensional data efficiently. From basic addition to complex cross products, these tools are essential for understanding spatial relationships and physical phenomena.

Matrix operations extend vector concepts to higher dimensions. They enable us to transform data, solve systems of equations, and model complex relationships. Mastering these operations unlocks powerful techniques for data analysis, computer graphics, and scientific computing.

Vector Operations

Basic vector operations

Top images from around the web for Basic vector operations
Top images from around the web for Basic vector operations
  • combines vectors component-wise, geometrically represented by tip-to-tail method (displacement)
  • finds difference between vectors, geometrically shown as vector between two points (relative position)
  • scales vector components, altering magnitude and possibly direction (vector scaling)

Dot and cross products

  • ab=a1b1+a2b2+a3b3a \cdot b = a_1b_1 + a_2b_2 + a_3b_3 measures vector similarity, equals abcosθ|a||b|\cos\theta (work calculation)
  • a×b=(a2b3a3b2,a3b1a1b3,a1b2a2b1)a \times b = (a_2b_3 - a_3b_2, a_3b_1 - a_1b_3, a_1b_2 - a_2b_1) creates perpendicular vector, magnitude equals parallelogram area (torque)
  • determines cross product direction, crucial for physics applications (angular momentum)

Matrix Operations

Matrix operations

  • /subtraction performed element-wise for same-sized matrices (image processing)
  • uses row-column dot products, non-commutative, requires compatible dimensions ()
  • flips matrix over main diagonal, ([AT](https://www.fiveableKeyTerm:at))T=A([A^T](https://www.fiveableKeyTerm:a^t))^T = A, (AB)T=BTAT(AB)^T = B^T A^T (data analysis)

Determinants and inverses

  • for 2x2 matrices: det(A)=adbcdet(A) = ad - bc for A=(abcd)A = \begin{pmatrix} a & b \\ c & d \end{pmatrix}, larger matrices use expansion by minors (area/volume scaling)
  • Determinant properties: det(AB)=det(A)det(B)det(AB) = det(A)det(B), det(AT)=det(A)det(A^T) = det(A) (linear transformations)
  • A1A^{-1} satisfies AA1=A1A=IAA^{-1} = A^{-1}A = I, calculated using adjoint method A1=1det(A)adj(A)A^{-1} = \frac{1}{det(A)}adj(A) (solving linear systems)
  • have zero determinant, no inverse exists (linear dependence)
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© 2024 Fiveable Inc. All rights reserved.
AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.

© 2024 Fiveable Inc. All rights reserved.
AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.
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