Hindawi Publishing Corporation Abstract and Applied Analysis Volume 2013, Article ID 705313, 8 pages http://dx.doi.org/10.1155/2013/705313 Research Article A Numerical Method for Partial Differential Algebraic Equations Based on Differential Transform Method Murat Osmanoglu and Mustafa Bayram Department of Mathematical Engineering, Chemical and Metallurgical Faculty, Yildiz Technical University, Esenler 34210, Istanbul, Turkey Correspondence should be addressed to Mustafa Bayram; msbayram@yildiz.edu.tr Received 14 January 2013; Accepted 28 February 2013 Academic Editor: Adem KilicΜ§man Copyright © 2013 M. Osmanoglu and M. Bayram. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We have considered linear partial differential algebraic equations (LPDAEs) of the form π΄π’π‘ (π‘, π₯) + π΅π’π₯π₯ (π‘, π₯) + πΆπ’(π‘, π₯) = π(π‘, π₯), which has at least one singular matrix of π΄, π΅ ∈ Rπ×π . We have first introduced a uniform differential time index and a differential space index. The initial conditions and boundary conditions of the given system cannot be prescribed for all components of the solution vector π’ here. To overcome this, we introduced these indexes. Furthermore, differential transform method has been given to solve LPDAEs. We have applied this method to a test problem, and numerical solution of the problem has been compared with analytical solution. 1. Introduction The partial differential algebraic equation was first studied by Marszalek. He also studied the analysis of the partial differential algebraic equations [1]. Lucht et al. [2– 4] studied the numerical solution and indexes of the linear partial differential equations with constant coefficients. A study about characteristics analysis and differential index of the partial differential algebraic equations was given by Martinson and Barton [5, 6]. Debrabant and Strehmel investigated the convergence of Runge-Kutta method for linear partial differential algebraic equations [7]. There are numerous LPDAEs applications in scientific areas given, for instance, in the field of Navier-Stokes equations, in chemical engineering, in magnetohydrodynamics, and in the theory of elastic multibody systems [4, 8–12]. On the other hand, the differential transform method was used by Zhou [13] to solve linear and nonlinear initial value problems in electric circuit analysis. Analysis of nonlinear circuits by using differential Taylor transform was given by KoΜksal and Herdem [14]. Using onedimensional differential transform, Abdel-Halim Hassan [15] proposed a method to solve eigenvalue problems. The two-dimensional differential transform methods have been applied to the partial differential equations [16– 19]. The differential transform method extended to solve differential-difference equations by Arikoglu and Ozkol [20]. Jang et al. have used differential transform method to solve initial value problems [21]. The numerical solution of the differential-algebraic equation systems has been studied by using differential transform method [22, 23]. In this paper, we have considered linear partial differential equations with constant coefficients of the form π΄π’π‘ (π‘, π₯) + π΅π’π₯π₯ (π‘, π₯) + πΆπ’ (π‘, π₯) = π (π‘, π₯) , (π‘, π₯) ∈ π½ × Ω, (1) where π½ = [0, ∞), Ω = [−π, π], π > 0, and π΄, π΅, πΆ ∈ Rπ×π . In (1) at least one of the matrices π΄, π΅ ∈ Rπ×π should be singular. If π΄ = 0 or π΅ = 0, then (1) becomes ordinary differential equation or differential algebraic equation, so we assume that none of the matrices π΄ or π΅ is the zero matrix. 2 Abstract and Applied Analysis Definition 1. Let πΌ∗ ∈ R+ be a number with πΌ∗ ≥ πΌ, such that for all π ∈ C with Re(π) ≥ πΌ∗ 2. Indexes of Partial Differential Algebraic Equation Let us consider (1), with initial values and boundary conditions given as follows: π’π (π‘, ±π) = 0 for π‘ ∈ π½, π’π (0, π₯) = π (π₯) for π₯ ∈ Ω, (2) where π ∈ Mπ΅πΆ ⊆ {1, 2, . . . , π}, Mπ΅πΆ is the set of indices of components of π’ for which boundary conditions can be prescribed arbitrarily, and π ∈ MπΌπΆ ⊆ {1, 2, . . . , π}, MπΌπΆ is the set of indices of components of π’ for which initial conditions can be prescribed arbitrarily. The initial boundary value problem (IBVP) (1) has only one solution where a function π’ is a solution of the problem, if it is sufficiently smooth, uniquely determined by its initial values (IVs) and boundary values (BVs), and if it solves the LPDAE point wise. Definition of the indexes can be given using the following assumptions. (i) Each component of the vectors π’, π’π‘ , and π satisfy the following condition: σ΅¨ σ΅¨σ΅¨ πΌπ‘ (3) σ΅¨σ΅¨π¦ (π‘, π₯)σ΅¨σ΅¨σ΅¨ ≤ ππ , πΌ ≥ 0, π‘ ≥ 0, where π and πΌ are independent of π‘ and π₯. (ii) (π΅, ππ΄ + πΆ), Re(π) > πΌ, called as the matrix pencil, is regular. (iii) (π΄, ππ π΅ + πΆ) is regular for all π, where ππ is an eigenvalue of the operator π2 /ππ₯2 together with prescribed BCs. (iv) The vector π(π‘, π₯) and the initial vector π(π₯) are sufficiently smooth. If we use Laplace transform, from assumption (ii), (1) can be transformed into π΅π’σΈ σΈ π (π₯) + (ππ΄ + πΆ) π’π (π₯) = ππ (π₯) + π΄π (π₯) , Re (π) > πΌ, (4) if π΅ is a singular matrix, then (4) is a DAE depending on the parameter π. To characterize Mπ΅πΆ, we introduce π ∈ M(π) π΅πΆ ⊆ {1, 2, . . . , π} as the set of indices of components of π’π for which boundary conditions can be prescribed arbitrarily. In order to define a spatial index, we need the Kronecker normal form of the DAE (4). Assumption (iii) guarantees that there are nonsingular matrices ππΏ,π , ππΏ,π ∈ Cπ×π such that 0 πΌ ), ππΏ,π π΅ππΏ,π = ( π1 0 ππΏ,π (5) π πΏ,π 0 ), ππΏ,π (ππ΄ + πΆ) ππΏ,π = ( 0 πΌπ2 where π πΏ,π ∈ Cπ1 ×π2 and ππΏ,π ∈ Rπ2 ×π2 is a nilpotent Jordan chain matrix with π1 + π2 = π. πΌπ is the unit matrix of order π. The Riesz index (or nilpotency) of ππΏ,π is denoted by ]πΏ,π ]πΏ,π ππΏ,π ]πΏ,π −1 0, ππΏ,π = =ΜΈ 0). Here, we will assume that there is a real number πΌ∗ ≥ πΌ such that the index set M(π) π΅πΆ is independent of the Laplace parameter π, provided Re(π) ≥ πΌ∗ . (i.e. (1) the matrix pencil (π΅, ππ΄ + πΆ) is regular, (π) (2) M(π) π΅πΆ is independent of π, i.e., Mπ΅πΆ = Mπ΅πΆ , (3) the nilpotency of ππΏ,π is ]πΏ ≥ 1. Then ]π,π₯ = 2]πΏ − 1 is called the “differential spatial index” of the LPDAE. If ]πΏ = 0, then the differential spatial index of LPDAE is defined to be zero. If we use Fourier transform, (1) can be transformed into Μ (π‘) + π΅π (π‘) Μ π (π‘) = π π΄Μ π’σΈ π (π‘) + (ππ π΅ + πΆ) π’ π π (6) with ππ (π‘) = (ππ1 (π‘), . . . , πππ (π‘))π and πππ (π‘) = 0 for π ∈ Mπ΅πΆ, π₯=π 1 πππ (π‘) = [ππσΈ (π₯) π’π (π‘, π₯) − ππ (π₯) π’π₯,π (π‘, π₯)]π₯=−π π (7) for π ∉ Mπ΅πΆ, which results from partial integration of the π term ∫−π π’π₯π₯ (π‘, π₯)ππ (π₯)ππ₯. If π΄ is a singular matrix, then (6) is a DAE depending on the parameter ππ which can be solved uniquely with suitable ICs under the assumptions (iv) and (v). Analogous to the case of the Laplace transform, the above assumption (iv) implies that there exist regular matrices ππΉ,π , ππΉ,π such that 0 πΌ ), ππΉ,π π΄ππΉ,π = ( π1 0 ππΉ,π ππΉ,π (ππ π΅ + πΆ) ππΉ,π 0 π = ( πΉ,π ). 0 πΌπ2 (8) With π πΉ,π ∈ Rπ1 ×π1 . ππΉ,π ∈ Rπ2 ×π2 is again a nilpotent Jordan chain matrix with Riesz index ]πΉ,π , where π1 + π2 = π. To characterize MπΌπΆ, we introduce M(π) πΌπΆ ⊆ {1, 2, . . . , π} Μ π for which initial as the set of indices of components of π’ conditions can be prescribed arbitrarily. Therefore, we always assume in the context of a Fourier analysis of π’ that M(π) πΌπΆ is = M . independent of π ∈ N+ , i.e., M(π) πΌπΆ πΌπΆ Definition 2. Assume for π = 1, 2, . . . that (1) the matrix pencil (π΄, ππ π΅ + πΆ) is regular, (π) (2) M(π) πΌπΆ is independent of π, i.e., MπΌπΆ = MπΌπΆ , (3) the nilpotency of ππΉ,π is ]πΉ,π = ]πΉ . Then the PDAE (1) is said to have uniform differential time index ]π,π‘ = ]πΉ . The differential spatial and time indexes are used to decide which initial and boundary values can be taken to solve the problem. Abstract and Applied Analysis 3 Theorem 8. Differential transform of the function π€(π₯, π¦) = π’(π₯, π¦) ⋅ V(π₯, π¦) is 3. Two-Dimensional Differential Transform Method π The two-dimensional differential transform of function π€(π₯, π¦) is defined as π (π, β) = π+β 1 π π€ (π₯, π¦) ] , [ π!β! π₯=0 ππ₯π ππ¦β (9) π¦=0 where it is noted that upper case symbol π(π, β) is used to denote the two-dimensional differential transform of a function represented by a corresponding lower case symbol π€(π₯, π¦). The differential inverse transform of π(π, β) is defined as ∞ ∞ π€ (π₯, π¦) = ∑ ∑ π (π, β) π₯π π¦β . (10) π=0 β=0 From (9) and (10), we obtain π₯π π¦β ππ+β π€ (π₯, π¦) ] [ . π!β! π₯=0 ππ₯π ππ¦β π=0 β=0 ∞ ∞ π€ (π₯, π¦) = ∑ ∑ (11) π¦=0 The concept of two-dimensional differential transform is derived from two-dimensional Taylor series expansion, but the method doesn’t evaluate the derivatives symbolically. Theorem 3. Differential transform of the function π€(π₯, π¦) = π’(π₯, π¦) ± V(π₯, π¦) is π (π, β) = π (π, β) ± π (π, β) , (12) see [17]. β π (π, β) = ∑ ∑π (π, β − π ) π (π − π, π ) , (17) π=0 π =0 see [17]. Theorem 9. Differential transform of the function π€(π₯, π¦) = π₯π π¦π is π (π, β) = πΏ (π − π, β − π) = πΏ (π − π) πΏ (β − π) , (18) see [17], where 1, πΏ (π − π) = { 0, π=π π =ΜΈ π, 1, πΏ (β − π) = { 0, β=π β =ΜΈ π. (19) Theorem 10. Differential transform of the function π€(π₯, π¦) = π(π₯ + π, π¦) is π π π (π, β) = ∑ ( ) ππ−π πΊ (π, β) . π (20) π=π Proof. From Definition 1, we can write ∞ ∞ π€ (π₯, π¦) = ∑ ∑ πΊ (π, β) (π₯ + π)π π¦β β=0 π=0 Theorem 4. Differential transform of the function π€(π₯, π¦) = ππ’(π₯, π¦) is π (π, β) = ππ (π, β) , (13) see [17]. Theorem 5. Differential transform of the function π€(π₯, π¦) = ππ’(π₯, π¦)/ππ₯ is π (π, β) = (π + 1) π (π + 1, β) , (14) see [17]. Theorem 6. Differential transform of the function π€(π₯, π¦) = ππ’(π₯, π¦)/ππ¦ is π (π, β) = (β + 1) π (π, β + 1) , (15) = πΊ (0, 0) + πΊ (0, 1) π¦ + ππΊ (1, 0) + πΊ (1, 0) π₯ + πΊ (0, 2) π¦2 + πΊ (1, 1) π₯π¦ + ππΊ (1, 1) π¦ + π2 πΊ (2, 0) + 2ππΊ (2, 0) π₯ + πΊ (2, 0) π₯2 + πΊ (0, 3) π¦3 + πΊ (1, 2) π₯π¦2 + ππΊ (1, 2) π¦2 + πΊ (2, 1) π₯2 π¦ + 2ππΊ (2, 1) π₯π¦ + π2 πΊ (2, 1) π¦ + π3 πΊ (3, 0) + 3π2 πΊ (3, 0) π₯ + 3ππΊ (3, 0) π₯2 + πΊ (3, 0) π₯3 + ⋅ ⋅ ⋅ , π€ (π₯, π¦) = [πΊ (0, 0) + ππΊ (1, 0) +π2 πΊ (2, 0) + π3 πΊ (3, 0) + ⋅ ⋅ ⋅] see [17]. + π₯ [πΊ (1, 0) + 2ππΊ (2, 0) + 3π2 πΊ (3, 0) + ⋅ ⋅ ⋅] Theorem 7. Differential transform of the function π€(π₯, π¦) = ππ+π π’(π₯, π¦)/ππ₯π ππ¦π is + π¦ [πΊ (0, 1) + ππΊ (1, 1) + π2 πΊ (2, 1) + ⋅ ⋅ ⋅] π (π, β) = (π + 1) (π + 2) ⋅ ⋅ ⋅ (π + π) (β + 1) × (β + 2) ⋅ ⋅ ⋅ (β + π ) π (π + π, β + π ) , see [17]. + π₯2 [πΊ (2, 0) + 3ππΊ (3, 0) + ⋅ ⋅ ⋅] (16) + π₯π¦ [πΊ (1, 1) + 2ππΊ (2, 1) + ⋅ ⋅ ⋅] + π¦2 [πΊ (0, 2) + ππΊ (1, 2) + ⋅ ⋅ ⋅] + ⋅ ⋅ ⋅ 4 Abstract and Applied Analysis ∞ ∞ π=0 π=1 = ∑ ππ πΊ (π, 0) + π₯ ∑ πππ−1 πΊ (π, 0) π π π π π=0 π=0 π=1 π=0 = ∑ ∑ ππ ππ πΊ (π, π) + π₯ ∑ ∑ πππ−1 ππ πΊ (π, π) ∞ ∞ π! (π − 2)!2! π=2 π π + π¦ ∑ ππ πΊ (π, 1) + π₯2 ∑ π=0 + π¦ ∑ ∑ πππ ππ−1 πΊ (π, π) π=0 π=1 ∞ π π π! ππ−2 ππ πΊ (π, π) (π − 2)!2! π=2 π=0 × ππ−2 πΊ (π, 0) + π₯π¦ ∑ πππ−1 πΊ (π, 1) + ⋅ ⋅ ⋅ , + π₯2 ∑ ∑ π=1 (21) π π + π₯π¦ ∑ ∑ ππππ−1 ππ−1 πΊ (π, π) + ⋅ ⋅ ⋅ . where π=1 π=1 ∞ ∞ ∞ π π€ (π₯, π¦) = ∑ ∑ ∑ ( ) ππ−π πΊ (π, β) π₯π π¦β π β=0 π=0 π=π (25) (22) Hence, we can write hence, ∞ ∞ π π π π (π, β) = ∑ ( ) ππ−π πΊ (π, β) . π (23) π=π π π π π€ (π₯, π¦) = ∑ ∑ ∑ ∑ ( ) ( ) β π β=0 π=0 π=π π=β (26) × ππ−π ππ−β πΊ (π, π) π₯π π¦β . Theorem 11. Differential transform of the function π€(π₯, π¦) = π(π₯ + π, π¦ + π) is π π π π π (π, β) = ∑ ∑ ( ) ( ) ππ−π ππ−β πΊ (π, π) . β π Using Definition 2, we obtain π (24) π=π π=β π π π π (π, β) = ∑ ∑ ( ) ( ) ππ−π ππ−β πΊ (π, π) . β π (27) π=π π=β Proof. From Definition 2, we can write ∞ ∞ β π€ (π₯, π¦) = ∑ ∑ πΊ (π, β) (π₯ + π)π (π¦ + π) β=0 π=0 Theorem 12. Differential transform of the function π€(π₯, π¦) = ππ+π π(π₯ + π, π¦ + π)/ππ₯π ππ¦π is = πΊ (0, 0) + πΊ (1, 0) π₯ + ππΊ (1, 0) + πΊ (0, 1) π¦ + ππΊ (0, 1) + πΊ (2, 0) π₯2 + 2ππΊ (2, 0) π₯ + π2 πΊ (2, 0) + πΊ (1, 1) π₯π¦ + ππΊ (1, 1) π₯ + ππΊ (1, 1) π¦ + πππΊ (1, 1) π (π, β) = (π + π)! (β + π )! π! β! π π ∑ ( × ∑ π=π+π π=β+π 3 2 + π πΊ (3, 0) + πΊ (2, 1) π₯ π¦ + ⋅ ⋅ ⋅ Proof. Let πΆ(π, β) be differential transform of the function π(π₯ + π, π¦ + π). From Theorem 7, we can write that differential transform of the function π€(π₯, π¦) is π€ (π₯, π¦) = [πΊ (0, 0) + ππΊ (1, 0) + ππΊ (0, 1) 2 +π πΊ (2, 0) + πππΊ (1, 1) + ⋅ ⋅ ⋅] + [πΊ (1, 0) + 2ππΊ (2, 0) + ππΊ (1, 1) +3π2 πΊ (3, 0) + 2πππΊ (2, 1) + ⋅ ⋅ ⋅] π₯ + [πΊ (0, 1) + ππΊ (1, 1) + 2ππΊ (0, 2) 2 +π πΊ (2, 1) + ⋅ ⋅ ⋅] π¦ + ⋅ ⋅ ⋅ (28) × ππ−π−π ππ−β−π πΊ (π, π) . + πΊ (0, 2) π¦2 + 2ππΊ (0, 2) π¦ + π2 πΊ (0, 2) + πΊ (3, 0) π₯3 + 3ππΊ (3, 0) π₯2 + 3π2 πΊ (3, 0) π₯ π π )( ) β+π π+π π (π, β) = (π + π)! (β + π )! πΆ (π + π, β + π ) , π! β! (29) from Theorem 4, we can write π πΆ (π + π, β + π ) = ∑ π π π )( ) ∑ ( β+π π+π π=π+π π=β+π × ππ−π−π ππ−β−π πΊ (π, π) . (30) Abstract and Applied Analysis 5 If we substitute (30) into (29), we find π (π, β) = Table 1: The numerical and exact solution of the test problem(32), where π’1 (π‘, π₯) is the exact solution and π’1∗ (π‘, π₯) is the numerical solution, for π₯ = 0.1. (π + π)! (β + π )! π! β! π × ∑ π π π )( ) ∑ ( β+π π+π π‘ (31) π=π+π π=β+π × ππ−π−π ππ−β−π πΊ (π, π) . 4. Application We have considered the following PDAE as a test problem: 1 1 −1 0 1 1 ( )π’ + ( )π’ + ( ) π’ = π, 0 0 π‘ −1 0 π₯π₯ −1 0 π‘ ∈ [0, ∞) , π₯ ∈ [−1, 1] , π’1 (π‘, 1) = π’1 (π‘, −1) = 0, π’2 (0, π₯) = π₯4 − 1, π’2 (π‘, 1) = π’2 (π‘, −1) = 0. (33) π π = ((π₯4 − 1) (cos π‘ − sin π‘) − 6π₯π−π‘ , −π−π‘ (π₯3 + 5π₯)) , (34) and the exact solutions are π’2 (π‘, π₯) = (π₯4 − 1) cos π‘. (35) If nonsingular matrices ππΉ,π , ππΉ,π , ππΏ,π , and ππΏ,π are chosen such as −ππ 1 0 −1 ππ − 1 ππΉ,π = ( ππΉ,π = ( ), 1 ), 1 −1 0 ππ − 1 (36) 1 0 −π − 1 0 π + 1 ), ππΏ,π = ( ππΏ,π = ( 1 ), 1 π 1 − π+1 π+1 matrices ππΉ,π π΄ππΉ,π and ππΏ,π π΅ππΏ,π are found as 1 0 ππΉ,π π΄ππΉ,π = ( ), 0 0 1 0 ππΏ,π π΅ππΏ,π = ( ). 0 0 (37) From (38), we have ππΏ,π = 0 and ππΉ,π = 0. Then the PDAE (32) has differential spatial index 1 and differential time index (π) 1. So, it is enough to take M(π) π΅πΆ = {1} and MπΌπΆ = {2} to solve the problem. Taking differential transformation of (32), we obtain (π + 1) π1 (π + 1, β) + (π + 1) π2 (π + 1, β) − (β + 1) (β + 2) π1 (π, β + 2) + π1 (π, β) |π’1 (π‘, π₯) − π’1∗ (π‘, π₯)| −0.0895789043 −0.0810543445 −0.0733410038 −0.0663616845 −0.0600465353 −0.0543323519 −0.0491619450 −0.0444835674 −0.0402503963 −0.0364200646 −0.0895789043 −0.0810543422 −0.0733409887 −0.0663616355 −0.0600464409 −0.0543322800 −0.0491621943 −0.0444849422 −0.0402546487 −0.0364305555 0 0.0000000023 0.0000000151 0.0000000490 0.0000000944 0.0000000719 0.0000002493 0.0000013748 0.0000042524 0.0000104909 Table 2: The numerical and exact solution of the test problem(32), where π’2 (π‘, π₯) is exact solution and π’2∗ (π‘, π₯) is numerical solution, for π₯ = 0.1. The right hand side function π is π’1 (π‘, π₯) = (π₯3 − π₯) π−π‘ , π’1∗ (π‘, π₯) (32) with initial values and boundary values π’1 (0, π₯) = π₯3 − π₯, 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 π’1 (π‘, π₯) (38) + π2 (π, β) = πΉ1 (π, β) , − (β + 1) (β + 2) π1 (π, β + 2) − π1 (π, β) = πΉ2 (π, β) . (39) π‘ 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 π’2 (π‘, π₯) π’2∗ (π‘, π₯) |π’2 (π‘, π₯) − π’2∗ (π‘, π₯)| −0.9949046649 −0.9799685711 −0.9552409555 −0.9209688879 −0.8774948036 −0.8252530813 −0.7647657031 −0.6966370386 −0.6215478073 −0.5402482757 −0.9949046653 −0.9799685778 −0.9552409875 −0.9209689778 −0.8774949653 −0.8252532000 −0.7647652653 −0.6966345778 −0.6215398875 −0.5402277778 0.0000000004 0.0000000067 0.0000000320 0.0000000899 0.0000001637 0.0000001187 0.0000004378 0.0000024608 0.0000079198 0.0000204979 The Taylor series of functions π1 and π2 about π₯ = 0, π‘ = 0 are 1 π1 (π‘, π₯) = − 1 + π‘ − 6π₯ + π‘2 + 6π₯π‘ 2 1 3 1 − π‘ − 3π₯π‘2 − π‘4 + π₯4 + π₯π‘3 6 24 1 1 1 6 (40) − π₯4 π‘ + π‘5 − π₯π‘4 + π‘ 120 4 720 1 1 1 − π₯4 π‘2 + π₯π‘5 + π₯4 π‘3 2 20 6 1 7 1 − π‘ − π₯π‘6 + ⋅ ⋅ ⋅ , 5040 120 5 π2 (π‘, π₯) = − 5π₯ + 5π₯π‘ − π₯π‘2 − π₯3 2 5 3 1 5 + π₯π‘ + π₯3 π‘ − π₯3 π‘2 − π₯π‘4 6 2 24 (41) 1 33 1 5 1 6 + π₯ π‘ + π₯π‘ − π₯π‘ 6 24 144 1 − π₯3 π‘4 + ⋅ ⋅ ⋅ . 24 6 Abstract and Applied Analysis 0.6 0.4 0.2 0 −0.2 −0.4 −0.6 −0.8 −1 0.4 0.2 0 −0.2 −0.4 0 π‘ −1 0.5 −1 0.5 1 π‘ −0.5 1 0 1.5 2 0.5 −0.5 0 1.5 2 π₯ 1 Figure 1: The graphic of the function π’1 (π‘, π₯) in the test problem (32). 0.2 0 0.5 π₯ 1 Figure 3: The graphic of the function π’2 (π‘, π₯) in the test problem (32). 0.6 0.4 0.2 0 −0.2 −0.4 −0.6 −0.8 −1 0.4 0 −1 0.5 −0.2 −0.4 0 −0.5 π‘ 0 −1 0.5 π‘ −0.5 1 0 1.5 2 0.5 π = 0, 1, . . . , 7, ∑(−1)π π1 (π, π) = 0, π=0 π₯ 1 π = 0, 1, . . . , 7. In order to write π = 0 and β = 0, 1, 2, 3, 4, 5 in (40), we have 2π1 (0, 2) + π1 (0, 0) = 0, 20π1 (0, 5) + π1 (0, 3) = 1, 6π1 (0, 3) + π1 (0, 1) = 5, 30π1 (0, 6) + π1 (0, 4) = 0, 12π1 (0, 4) + π1 (0, 2) = 0, 42π1 (0, 7) + π1 (0, 5) = 0. (44) If we take π = 0 in (43) and (44), we obtain π1 (0, 0) + π1 (0, 1) + π1 (0, 2) + π1 (0, 3) (42) π=0 7 2 0.5 1 The values πΉ1 (π, β) and πΉ2 (π, β) in (39) and (40) are coefficients of polynomials (41) and (42). If we use Theorem 3 for boundary values, we obtain 7 0 1.5 Figure 4: The graphic of the function π’2∗ (π‘, π₯) in the test problem (32). π₯ Figure 2: The graphic of the function π’1∗ (π‘, π₯) in the test problem (32). ∑π1 (π, π) = 0, 1 (43) + π1 (0, 4) + π1 (0, 5) + π1 (0, 6) + π1 (0, 7) = 0, π1 (0, 0) − π1 (0, 1) + π1 (0, 2) − π1 (0, 3) + π1 (0, 4) − π1 (0, 5) + π1 (0, 6) − π1 (0, 7) = 0. (45) Abstract and Applied Analysis 7 From (45) and (46), we find π2 (4, 0) = − π1 (0, 0) = 0, π1 (0, 1) = −1, π1 (0, 2) = 0, π1 (0, 3) = 1, π1 (0, 4) = 0, π1 (0, 5) = 0, π1 (0, 6) = 0, π2 (5, 2) = 0, π1 (1, 3) = −1, π1 (1, 4) = 0, π1 (1, 2) = 0, 1 π1 (2, 1) = − , 2 1 π1 (2, 3) = , 2 π1 (2, 4) = 0, π1 (2, 5) = 0, π1 (3, 0) = 0, 1 π1 (3, 1) = , 6 π1 (3, 2) = 0, 1 π1 (3, 3) = − , 6 π1 (3, 4) = 0, π1 (4, 0) = 0, π1 (4, 1) = − 1 , 24 π1 (4, 2) = 0, π1 (5, 2) = 0, π1 (6, 0) = 0, π1 (5, 1) = + 1 6 1 42 +π₯ + π‘ − π₯ π‘ + ⋅⋅⋅. 720 2 1 , π1 (6, 1) = − 720 (47) Using the initial values for the second component, we obtain the following coefficients: π2 (0, 1) = 0, π2 (0, 2) = 0, π2 (0, 3) = 0, π2 (0, 4) = 1, π2 (0, 5) = 0, (48) The coefficients of the π’2 can be found using (47), (48), (49), and taking π = 0, 1, 2, . . . and β = 0, 1, 2, . . . in (39) as follows: π2 (1, 3) = 0, π2 (1, 4) = 0, π2 (1, 5) = 0, π2 (1, 6) = 0, π2 (2, 1) = 0, π2 (2, 2) = 0, π2 (2, 3) = 0, 1 π2 (2, 4) = − , 2 π2 (2, 5) = 0, π2 (3, 0) = 0, π2 (3, 1) = 0, π2 (3, 2) = 0, π2 (3, 3) = 0, π2 (3, 4) = 0, π2 (4, 1) = 0, π2 (4, 2) = 0, π2 (4, 3) = 0, Numerical and exact solution of the given problem has been compared in Tables 1 and 2, and simulations of solutions have been depicted in Figures 1, 2, 3, and 4, respectively. 5. Conclusion The computations associated with the example discussed above were performed by using Computer Algebra Techniques [24]. We show the results in Tables 1 and 2 for the solution of (32) by numerical method. The numerical values on Tables 1 and 2 obtained above are in full agreement with the exact solutions of (32). This study has shown that the differential transform method often shows superior performance over series approximants, providing a promising tool for using in applied fields. References π2 (0, 7) = 0. π2 (1, 2) = 0, (51) 4 1 , 120 π2 (0, 0) = −1, (50) 1 1 6 1 34 π₯π‘5 − π₯π‘ + π₯ π‘ + ⋅ ⋅ ⋅ , 120 720 24 1 1 π’2∗ (π‘, π₯) = − 1 + π‘2 − π‘4 2 24 π1 (7, 0) = 0. π2 (0, 6) = 0, 1 1 π’1∗ (π‘, π₯) = − π₯ + π₯π‘ − π₯π‘2 + π₯3 + π₯π‘3 2 6 1 1 1 − π₯3 π‘ + π₯3 π‘2 − π₯π‘4 − π₯3 π‘3 2 24 6 π1 (2, 2) = 0, π1 (5, 0) = 0, π2 (6, 1) = 0, If we write the above values in (39) and (40), then we have π1 (1, 5) = 0, π1 (2, 0) = 0, 1 , 24 1 , 720 (49) π1 (1, 6) = 0, π1 (4, 3) = π2 (5, 1) = 0, π2 (7, 0) = 0. π1 (0, 7) = 0. π1 (1, 1) = 1, π2 (5, 0) = 0, π2 (6, 0) = (46) In this manner, from (40), (44), and (45), the coefficients of the π’1 are obtained as follows: π1 (1, 0) = 0, 1 , 24 [1] W. Marszalek, Analysis of partial differential algebraic equations [Ph.D. thesis], North Carolina State University, Raleigh, NC, USA, 1997. [2] W. Lucht, K. Strehmel, and C. 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