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  2. Index notation - Wikipedia

    en.wikipedia.org/wiki/Index_notation

    A vector treated as an array of numbers by writing as a row vector or column vector (whichever is used depends on convenience or context): = (), = Index notation allows indication of the elements of the array by simply writing a i, where the index i is known to run from 1 to n, because of n-dimensions. [1]

  3. Raising and lowering indices - Wikipedia

    en.wikipedia.org/wiki/Raising_and_lowering_indices

    Concretely, in the case where the vector space has an inner product, in matrix notation these can be thought of as row vectors, which give a number when applied to column vectors. We denote this by V ∗ := Hom ( V , K ) {\displaystyle V^{*}:={\text{Hom}}(V,K)} , so that α ∈ V ∗ {\displaystyle \alpha \in V^{*}} is a linear map α : V → K ...

  4. nth root - Wikipedia

    en.wikipedia.org/wiki/Nth_root

    The integer n is called the index or degree, and the number x of which the root is taken is the radicand. A root of degree 2 is called a square root and a root of degree 3, a cube root. Roots of higher degree are referred by using ordinal numbers, as in fourth root, twentieth root, etc. The computation of an n th root is a root extraction.

  5. One-step method - Wikipedia

    en.wikipedia.org/wiki/One-step_method

    The latter are also suitable for so-called stiff initial value problems. The simplest and oldest one-step method, the explicit Euler method, was published by Leonhard Euler in 1768. After a group of multi-step methods was presented in 1883, Carl Runge, Karl Heun and Wilhelm Kutta developed significant improvements to Euler's method around 1900 ...

  6. Calculator input methods - Wikipedia

    en.wikipedia.org/wiki/Calculator_input_methods

    In reverse Polish notation, [7] also known as postfix notation, all operations are entered after the operands on which the operation is performed. Reverse Polish notation is parenthesis-free, which usually leads to fewer button presses needed to perform an operation. By the use of a stack, one can enter formulas without the need to rearrange ...

  7. de Bruijn index - Wikipedia

    en.wikipedia.org/wiki/De_Bruijn_index

    In mathematical logic, the de Bruijn index is a tool invented by the Dutch mathematician Nicolaas Govert de Bruijn for representing terms of lambda calculus without naming the bound variables. [1] Terms written using these indices are invariant with respect to α-conversion , so the check for α-equivalence is the same as that for syntactic ...

  8. Multi-index notation - Wikipedia

    en.wikipedia.org/wiki/Multi-index_notation

    Multi-index notation is a mathematical notation that simplifies formulas used in multivariable calculus, partial differential equations and the theory of distributions, by generalising the concept of an integer index to an ordered tuple of indices.

  9. Rodrigues' rotation formula - Wikipedia

    en.wikipedia.org/wiki/Rodrigues'_rotation_formula

    The above result can be written in index notation as follows. The elements of the matrix for an active rotation by an angle θ {\displaystyle \theta } about an axis n are given by R i j = cos ⁡ θ δ i j + ( 1 − cos ⁡ θ ) n i n j − sin ⁡ θ ϵ i j k n k . {\displaystyle R_{ij}=\cos \theta \,\delta _{ij}+(1-\cos \theta )n_{i}n_{j ...