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BRIEF MESSAGE
Best quadrature formulas calculation of curvilinear integrals for some classes of functions and currves
M. Sh. Shabozov, M. K. Abdukarimzoda Tajik National University
(Dushanbe)
Abstract:
For an approximate calculation of a curvilinear integral J(f;Γ):=∫Γf(x1,x2,…,xm)dt when the curve Γ is given by parametric equations x1=φ1(t),x2=φ2(t),…,xm=φm(t),0≤t≤L the quadrature formula is entered into consideration J(f;Γ):≈N∑k=1pkf(φ1(tk),φ2(tk),…,φm(tk)), where P={pk}Nk=1 and T:={tk:0≤t1<t2<⋯<tN≤L}– are arbitrary vector coefficients and nodes. Let Hω1,…,ωm[0,L]– sets of curves Γ, whose coordinate functions φi(t)∈Hωi[0,L] (i=¯1,m), where ωi(t) (i=¯1,m)– are given moduli of continuity Mω,pρ– functions class f(M), defined in point M∈Γ, such for any two points M′=M(x′1,x′2,…,x′m), M′′=M(x′′1,x′′2,…,x′′m) belonging to a curve Γ∈Hω1,…,ωm[0,L] satsify the condition |f(M′)−f(M′′)|⩽ω(ρp(M′,M′′)), where ρp(M′,M′′)={m∑i=1|x′i−x′′i|p}1/p, 1≤p≤∞, ω(t)– given moduls of continuity. It is proved that among all quadrature formulas of the above from, the best for a class of functions Mω,pρ and a class of curves Hω1,…,ωm[0,1], is the formula of average rectangles.
The exact error estimate of the best quadrature formula is calculated for all the functional classes under consideration and the curves are given a generalization for more general classes of functions.
Keywords:
curvilinear integral, quadrature formula, error, rectangle formula, functions class, nodes.
Received: 21.02.2020 Accepted: 22.10.2020
Citation:
M. Sh. Shabozov, M. K. Abdukarimzoda, “Best quadrature formulas calculation of curvilinear integrals for some classes of functions and currves”, Chebyshevskii Sb., 21:3 (2020), 250–261
Linking options:
https://www.mathnet.ru/eng/cheb940 https://www.mathnet.ru/eng/cheb/v21/i3/p250
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Abstract page: | 126 | Full-text PDF : | 47 | References: | 27 |
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