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Exponential smoothing was first suggested in the statistical literature without citation to previous work by Robert Goodell Brown in 1956, [3] and then expanded by Charles C. Holt in 1957. [4] The formulation below, which is the one commonly used, is attributed to Brown and is known as "Brown’s simple exponential smoothing". [ 5 ]
This has the convenient implication for 2 × 2 and 3 × 3 rotation matrices that the trace reveals the angle of rotation, θ, in the two-dimensional space (or subspace). For a 2 × 2 matrix the trace is 2 cos θ, and for a 3 × 3 matrix it is 1 + 2 cos θ. In the three-dimensional case, the subspace consists of all vectors perpendicular to the ...
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]
Using the x-convention, the 3-1-3 extrinsic Euler angles φ, θ and ψ (around the z-axis, x-axis and again the -axis) can be obtained as follows: = (,) = = (,) Note that atan2( a , b ) is equivalent to arctan a / b where it also takes into account the quadrant that the point ( b , a ) is in; see atan2 .
p ↦ q p for q = 1 + i + j + k / 2 on the unit 3-sphere. Note this one-sided (namely, left) multiplication yields a 60° rotation of quaternions. The length of is √ 3, the half angle is π / 3 (60°) with cosine 1 / 2 , (cos 60° = 0.5) and sine √ 3 / 2 , (sin 60° ≈ 0.866). We are therefore dealing with a ...
We only consider stretches along the x-axis and y-axis. A stretch along the x-axis has the form x' = kx; y' = y for some positive constant k. (Note that if k > 1, then this really is a "stretch"; if k < 1, it is technically a "compression", but we still call it a stretch. Also, if k = 1, then the transformation is an identity, i.e. it has no ...
In mathematics, a rotation of axes in two dimensions is a mapping from an xy-Cartesian coordinate system to an x′y′-Cartesian coordinate system in which the origin is kept fixed and the x′ and y′ axes are obtained by rotating the x and y axes counterclockwise through an angle .
The result is the Riemann surface domain on which f(z) = z 1/2 is single-valued and holomorphic (except when z = 0). [6] To understand why f is single-valued in this domain, imagine a circuit around the unit circle, starting with z = 1 on the first sheet. When 0 ≤ θ < 2π we are still on the first sheet.