Results 21 to 30 of about 1,636,257 (267)
On a solvable class of nonlinear difference equations of fourth order
Electronic Journal of Qualitative Theory of Differential Equations, 2022 We consider a class of nonlinear difference equations of the fourth order, which extends some equations in the literature. It is shown that the class of equations is solvable in closed form explaining theoretically, among other things, solvability of ...
Stevo Stevic +3 more
doaj +1 more source
Solution Generating with Perfect Fluids [PDF]
General Relativity and Gravitation, 1997 We apply a technique, due to Stephani, for generating solutions of the Einstein-perfect fluid equations. This technique is similar to the vacuum solution generating techniques of Ehlers, Harrison, Geroch and others. We start with a ``seed'' solution of the Einstein-perfect fluid equations with a Killing vector.
Garfinkle, David +2 more
openaire +2 more sources
Open Mathematics, 2016 In this paper, we find the formula of general solution for a generalized impulsive differential equations of fractional-order q ∈ (2, 3).
Zhang Xianmin +5 more
doaj +1 more source
Molecules, 2022 The crystallization of the poorly soluble drug nitrofurantoin (NFT) with 4-aminopyridine (4AmPy) resulted in three multicomponent solid forms with different hydration levels: anhydrous salt [NFT+4AmPy] (1:1), salt monohydrate [NFT+4AmPy+H2O] (1:1:1), and
Denis E. Boycov +4 more
doaj +1 more source
Solutions of a System of Two Higher-Order Difference Equations in Terms of Lucas Sequence
Universal Journal of Mathematics and Applications, 2019 In this paper we give some theoretical explanations related to the representation for the general solution of the system of the higher-order rational difference equations $$ x_{n+1} = \frac{5 y_{n-k}-5}{y_{n-k}}, \qquad y_{n+1} = \frac{5 x_{n-k}-5}{x_{
Amira Khelifa +2 more
doaj +1 more source
On Relationships between a Linear Matrix Equation and Its Four Reduced Equations
Axioms, 2022 Given the linear matrix equation AXB=C, we partition it into the form A1X11B1+A1X12B2+A2X21B1+A2X22B2=C, and then pre- and post-multiply both sides of the equation by the four orthogonal projectors generated from the coefficient matrices A1, A1, B1, and ...
Bo Jiang, Yongge Tian, Ruixia Yuan
doaj +1 more source
ON GENERAL SOLUTIONS OF EINSTEIN EQUATIONS [PDF]
International Journal of Geometric Methods in Modern Physics, 2011 We show how the Einstein equations with cosmological constant (and/or various types of matter field sources) can be integrated in a very general form following the anholonomic deformation method for constructing exact solutions in four- and five-dimensional gravity (S. Vacaru, IJGMMP 4 (2007) 1285).
openaire +3 more sources
On a two-dimensional solvable system of difference equations
Electronic Journal of Qualitative Theory of Differential Equations, 2018 Here we solve the following system of difference equations $$x_{n+1}=\frac{y_ny_{n-2}}{bx_{n-1}+ay_{n-2}},\quad y_{n+1}=\frac{x_nx_{n-2}}{dy_{n-1}+cx_{n-2}},\quad n\in\mathbb{N}_0,$$ where parameters $a, b, c, d$ and initial values $x_{-j},$ $y_{-j}$, $j=
Stevo Stevic
doaj +1 more source
Surfactant-Switched Positive/Negative Electrorheological Effect in Tungsten Oxide Suspensions
Molecules, 2019 The electrorheological (ER) effect was experimentally observed in dielectric suspensions containing tungsten oxide (WO3) modified with surfactant molecules (sodium dodecyl sulfate (SDS) and dodecylamine (DDA)) in electric fields up to several kilovolts ...
Alexander V. Agafonov +7 more
doaj +1 more source