J. Nig. Soc. Phys. Sci. 2 (2020) 12–25 Journal of the Nigerian Society of Physical Sciences Original Research Block Third Derivative Trigonometrically-Fitted Methods for Stiff and Periodic Problems R. I. Abdulganiya,∗, O. A. Akinfenwab, O. A. Yusuffb, O. E. Enobaborc, S. A. Okunugab aDistance Learning institute, University of Lagos, Nigeria bDepartment of Mathematics, University of Lagos, Nigeria cDepartment of Mathematics, Yaba College of Technology, Lagos, Nigeria Abstract This article constructed and implemented a family of a third derivative trigonometric fitted method of order k + 3 whose coefficients are functions of frequency and step size for the integration of systems of first-order stiff and periodic Initial Value Problems. The Block Third Derivative Trigonometric Fitted methods (BTDTFMs) are constructed via multistep collocation technique and applied in block form as simultaneous numer- ical integrators which make them self-starting. The basic properties of the BTDTFMs are analyzed and presented. The accuracy and efficiency of the methods based on number of function evaluation are established through some standard numerical examples which are either stiff or periodic in nature. Keywords: Convergence, Frequency, Stiff, Trigonometrically-Fitted. Article History : Received: 02 January 2020 Received in revised form: 16 February 2020 Accepted for publication: 17 February 2020 Published: 28 February 2020 c©2020 Journal of the Nigerian Society of Physical Sciences. All rights reserved. Communicated by: T. Latunde 1. Introduction A-stable methods are of great importance in solving stiff problems but put stark limitations on the choice of suitable methods for stiff problems. Dahlquist [1] established that the most accurate A-stable linear multistep method has order 2. The search for higher-order A-stable multistep method is car- ried out in the following three major directions (Biala et al. [2]): 1. Use of higher derivatives of the solution; 2. Incorporating additional stages and hybrid points; ∗Corresponding author tel. no: +2348035195870 Email addresses: profabdulcalculus@gmail.com (R. I. Abdulganiy), akinolu35@yahoo.com (O. A. Akinfenwa), olaoluwa.yusuff@gmail.com (O. A. Yusuff), enobaborosaretin@yahoo.com (O. E. Enobabor), waleokunuga@gmail.com (S. A. Okunuga) 3. Incorporating super future points. Many numerical methods have been developed along these three directions which include but not limited to Gear [3], En- right [4], Cash [5], Wu [6], Hojjati [7], Jator [8], Sahi et al. [9], Ngwane and Jator [10], Akinfenwa et al. [11,12,13], Mehdizadeh et al [14] and Abdulganiy et al. [15]. Method based on Simpson’s was explored by Akinfenwa et al. [16] while methods bases on exponential fitting were consid- ered in Okunuga [17], Vaquero and Vigo-Aguiar [18], Abhuli- men et al. [19,20], Ehigie et al. [21] and Adesanya et al. [22] to numerically approximate stiff problems. Although the expo- nential fitting methods for solving stiff problems were easy to implement, tedious mathematical analyses are involved in ob- taining the A-stability. Periodic problems, on the other hand, have received much attention in the past few decades. The methods for solving peri- 12 Abdulganiy et al. / J. Nig. Soc. Phys. Sci. 2 (2020) 12–25 13 odic problems according to Yakubu et al., [23] can be classified into two: methods with constant coefficients and methods hav- ing coefficients depending on the frequency of the problems. If a good estimate of the frequency or some suitable substitute is known in advance, a linear multistep method can be used for the integration of periodic problems (Vanden Berghe et al., [24] and Van de Vyver [25]). The idea of using basis function which integrates a set of linearly independent function exactly other than polynomial can be traced to the work of Gautchi [26] and Lyche [27]. Many of such extension has been discussed in Coleman and Duxbury [28], Ixaru et al. [29], Vanden Berghe and his collaborators ([24], [30,31]), Simos [32,33], Tsitouras and Simos [34], Nguyen et al. [35], Senu et al. [36], Jator and his collaborators [37-41], Jator [42] and Abdulganiy and his collaborators [43-45]. In what follows, a Continuous third Derivative Method with Trigonometric Coefficients (CTDMTC) is derived via a mul- tistep collocation technique for which the approximate inter- polating function is a linear combination of polynomial and trigonometric terms. The CTDMTC is used to generate a family of Third Derivative Trigonometrically-Fitted Method (TDTFM) and some other discrete methods as by-products that are com- bined together into a Block Third Derivative Trigonometrically- Fitted Method (BTDTFM). The BTDTFM is applied as a simul- taneous numerical integrator for the integration of the system of first-order Ordinary Differential Equations (ODEs) y ′ (t) = f (t, y (t)) , y (t0) = y0, t ∈ [t0, tN ] (1) where f satisfies the Lipschitz condition with a periodic so- lution whose frequency is known in advance. Stiff or/and peri- odic differential equation of the form in equation (1) frequently arises in many area of Science and Engineering, a list of such are provided in Jator and Agyingi [46], Varden Berghe et al. [24] and Ndukum et al. [47]. The methods in this paper is dif- ferent from the methods in Jator [48,49] and Akinfenwa [50] in that they are used to solve system of first-order ODEs while the methods in Jator [48,49] are direct numerical integrators of general second-order ODEs and the methods in Akinfenwa [50] are hybrid in nature respectively. Some of the advantages of continuous methods include but not restricted to providing defect control (Enright [51]) and ability to produce complementary methods which are combined and applied in block-by-block fashion (Onumanyi et al. [52], Akinfenwa et al. [11,13]). The foremost block methods are credited to Milne [53], Rosser [54], Shampine and Watts [55] and Chu and Hamilton [56] and are implemented in predictor- corrector modes that reduce the stability properties of the meth- ods. The block method in this paper is implemented without the use of predictors. According to Jator and Agyingi [46], for a block method, it is needless to make a function evaluation at the preliminary part of the original block since at all blocks (with exception of the first block) the first function evaluation is previously known from the previous block. The rest of this paper is arranged as follows: the theoretical and basic elements of the BTDTFM is discussed in section 2. The basic properties of the methods are discussed in section 3. In section 4, the estimation of the computational frequency is discussed while numerical experiments are presented in section 5. Finally, section 6 concludes the paper. 2. Theoretical and Basic Elements of the BTDTFM The k−step third derivative method has the form yn+k−yn+k−1 = h k∑ j=0 β j (u) fn+ j+h 2δk (u) gn+k+h 3γk (u) ln+k(2) where u = ωh ,ω is the frequency, β j,δk,γk which depends on frequency and step size are parameters to be determined uniquely. Also, yn+k is the numerical approximation to exact solution y (xn+k) and fn+ j = f ( xn+ j , yn+ j ) , gn+k = d f (x, y (x)) d x | x = xn+k y = yn+k ln+k = d2 f (x, y (x)) d x2 | x = xn+k y = yn+k In order to obtain (2), the exact solution y (x) is approxi- mated on the interval [xn , xn+k] by the interpolating function I (x) given by I (x) = k+1∑ j=0 a j x j + ak+2sin(ωx) + ak+3cos(ωx) (3) Imposing conditions in equations (4) and equation (4) below on equation (3) I ( xn+ j ) = yn+ j (4)  I ′ ( xn+ j ) = fn+ j j = 0(1)k I ′′ ( xn+ j ) = gn+ j j = k I ′′′ ( xn+ j ) = ln+ j j = k (5) lead to a system of (k + 4) equations which is solved using a Computer Algebra System (CAS) such as Maple. The deriva- tion of the methods manually becomes more difficult for k ≥ 2. Hence, the explorations of CAS become necessary. The contin- uous form is developed by substituting the values of a j, j = 0 (1) (k + 3) into equation equation (3). After some algebraic manipulations, the continuous form is obtained as the expres- sion equation (6). I (x) = yn+k−1+h k∑ j=0 β j (u, x) fn+ j+h 2δk(u, x)gn+k+h 3γk(u, x)ln+k(6) The continuous method in equation (6) is evaluated at x = xn+k to generate the principal method given by 13 Abdulganiy et al. / J. Nig. Soc. Phys. Sci. 2 (2020) 12–25 14 yn+k = yn+k−1 + h k∑ j=0 β j (cos (u) , sin(u)) fn+ j+h 2δk (cos (u) , sin (u) ) gn+k + h 3γk(cos (u) , sin(u))ln+k (7) while the (k − 1) secondary methods are obtained as yn+i = yn+k−1 + h k∑ j=0 β j(cos (u) , sin(u)) fn+ j+h 2δk(cos (u) , sin(u))gn+k + h 3γk(cos (u) , sin(u))ln+k (8) by evaluating equation (6) at x = xn+i , i = 1, 2, . . . , k − 1. Following the steps discussed above, the secondary and principal methods for k = 2 and k = 3, their coefficients and the corre- sponding power series conversion up to O ( u10 ) are given as follows For k = 2, yn = yn+1 + hβ0,1 (cos(u) , sin(u) ) fn + hβ1,1 (cos(u) , sin(u) ) fn+1 +h2δ2,1 (cos(u) , sin(u) )gn+1 + h3γ2,1 (cos(u) , sin(u) )ln+1 (9) yn+2 = yn+1 + hβ0 (cos(u) , sin(u) ) fn + hβ1 (cos(u) , sin(u) ) fn+1 + hβ2 (cos(u) , sin(u) ) fn+2 +h2δ2 (cos(u) , sin(u) ) gn+2 + h3γ2 (cos(u) , sin(u) ) ln+2 (10)  β0,1 = 1 6 ( −14sin (u) u3 + 5u4 − 12cos (u) u2 − 6cos (2u) u2 + 12sin (2u) u + 6u2 − 24cos (u) + 12cos (2u) + 12 ) / (( −2u − 2cos (2u) u − sin (2u) u2 − 4sin (u) + 2sin (2u) + 4cos (u) u + 4sin (u) u2 − 2u3 ) u ) β1,1 = 1 6 (( −7u3 + 18u ) sin(2u) + ( −21u2 + 6 ) cos (2u) − 4u4 + 12cos (u) u2 − 3u2 − 12sin (u) u − 6 ) / ((( 1 2 u 2 − 1 ) sin (2u) + u3 − 2sin (u) u2 − 2cos (u) u + cos (2u) u + u + 2sin(u) ) u ) β2,1 = 1 6 (( 8u3 − 12u ) sin(2u) + u4 + 10sin(u) u3 − 12cos (u) u2 + 24cos (2u) u2 − 24cos (u) + 24 ) / (( −4sin (u) u2 + sin (2u) u2 + 2u3 − 4cos (u) u + 2cos (2u) u + 4sin (u) − 2sin(2u) + 2u ) u ) δ2,1 = 1 6 ( 8sin (u) u3 + 5sin(2u) u3 − 12cos (u) u2 − 12cos (2u) u2 − 12sin (u) u + 6sin (2u) u − 48cos (u) + 12cos (2u) + 36 ) / (( −2u − 2cos (2u) u − sin (2u) u2 − 4sin (u) + 2sin (2u) + 4cos (u) u + 4sin (u) u2 − 2u3 ) u ) γ2,1 = (( −5u2 + 18 ) cos (2u) − 8cos (u) u2 + u2 − 16sin (u) u + 20sin (2u) u − 48cos (u) + 30 ) / ( 12cos (2u) u2 + 6 ( 2u3 − 4sin (u) u2 + sin (2u) u2 − 4cos (u) u + 2u + 4sin (u) − 2sin (2u) ) u ) (11)  β0,1 = − 49 160 − 13 1680 u 2 − 277 1728000 u 4 − 14911 13970880000 u 6 + 3775394358914560000 u 8 β1,1 = − 13 10 + 67 2100 u 2 + 289378000 u 4 + 7703873180000 u 6 − 334687 1362160800000 u 8 β2,1 = 97 160 − 29 1200 u 2 − 7309 12096000 u 4 − 108337 13970880000 u 6 + 346729721794572800000 u 8 δ2,1 = − 33 80 + 23 1400 u 2 + 179403200 u 4 + 155712328480000 u 6 − 263267 3632428800000 u 8 γ2,1 = 23 240 − 1 2100 u 2 − 373 6048000 u 4 − 15901 6985440000 u 6 − 11203 222393600000 u 8 (12)  β0 = 1 6 (( −2u3 + 24u ) sin(u) − u4 − 12cos (u) u2 + 24cos (u) − 24 ) / (( −4sin (u) u2 + sin (2u) u2 + 2u3 − 4cos (u) + 2cos (2u) u + 4sin (u) − 2sin (2u) + 2u ) u ) β1 = 1 6 (( u3 − 6u ) sin(2u) + ( 3u2 − 6 ) cos (2u) + 4 u4 + 12cos (u) u2 − 3u2 − 12sin (u) u + 6 ) / ( u (( 1 2 u 2 − 1 ) sin (2u) + u3 − 2sin (u) u2 − 2cos (u) u + cos (2u) u + u + 2sin (u) )) β2 = 1 6 ( 22sin(u) u3 + sin(2u) u3 − 5u4 + 36cos (u) u2 − 6cos (2u) u2 − 24sin (u) u − 18u2 + 24cos (u) − 12cos (2u) − 12 ) / (( −2u − 2cos (2u) u − sin (2u) u2 − 4sin (u) + 2sin (2u) + 4cos (u) u + 4sin (u) u2 − 2u3 ) u ) δ2 = 1 6 ( −8sin (u) u3 + sin (2u) u3 − 12cos (u) u2 − 12sin (u) u + 6sin (2u) u + 12u2 − 48cos (u) + 12cos (2u) + 36 ) / (( −2u − 2cos (2u) u − sin (2u) u2 − 4sin (u) + 2sin (2u) + 4cos (u) u + 4sin (u) u2 − 2u3 ) u ) γ2 = 1 6 ((−u2 +6)cos(2u) +8cos(u) u2 +5u2−32sin(u) u+4sin(2u) u−48cos(u) +42) ((−4sin(u) u2 +sin(2u) u2 +2u3−4cos(u)u +2cos(2u) u+4sin(u) )−2sin(2u) +2u)u (13) 14 Abdulganiy et al. / J. Nig. Soc. Phys. Sci. 2 (2020) 12–25 15 β0 = − 1 160 − 1 1680 u 2 − 53 1728000 u 4 − 15119 13970880000 u 6 − 115693 4358914560000 u 8 β1 = 3 10 + 1 700 u 2 + 41378000 u 4 + 3847873180000 u 6 + 1658171362160800000 u 8 β2 = 113 160 − 1 1200 u 2 − 941 12096000 u 4 − 46433 13970880000 u 6 − 2074607 21794572800000 u 8 δ2 = 17 80 + 1 4200 u 2 + 19403200 u 4 + 52192328480000 u 6 + 831191210809600000 u 8 γ2 = 7 240 + 1 2100 u 2 + 436048000 u 4 − 269 6985440000 u 6 − 84803 10897286400000 u 8 (14) For k = 3, yn=yn+2+hβ0,1 (ucos (u) , sin(u)) fn+hβ1,1(cos (u) , sin(u)) fn+1+hβ2,1(cos (u) , sin(u)) fn+2 +hβ3,1(cos (u) , sin(u)) fn+3+h2δ3,1(cos (u) , sin(u))gn+3+h3γ3,1(cos (u) , sin(u))ln+3 (15) yn+1=yn+2+hβ0,2 (cos (u) , sin(u)) fn+hβ1,2 (ucos (u) , sin(u)) fn+1+hβ2,2(cos (u) , sin(u)) fn+2 +hβ3,2(cos (u) , sin(u)) fn+3+h2δ3,2(cos (u) , sin(u))gn+3+h3γ3,2(cos (u) , sin(u))ln+3 (16) yn+3=yn+2+hβ0 (cos (u) , sin(u)) fn+hβ1 (cos (u) , sin(u)) fn+1+hβ2 (ucos (u) , sin(u)) fn+2 +hβ3 (cos (u) , sin(u)) fn+3+h2δ3(cos (u) , sin(u))gn+3+h3γ3(cos (u) , sin(u))ln+3 (17)  β0,1 = 1 3 (−16sin(u)u 3 + 17sin(2u)u3 + 6u4 − 30cos(u)u2 + 6cos(3u)u2 + 48cos(2u)u2 + 90sin(u)u −18sin (3u) u − 54sin (2u) u + 12u2 + 21cos (u) − 21cos (3u) + 24cos (2u) − 24)/ρ β1,1 = 1 3 (−81sin (u) u 3 − 17sin (3u) u3 + 24u4 − 117cos (u) u2 − 75cos (3u) u2 + 30sin (u) u + 126sin (3u) u −60sin (2u) u + 48u2 − 78cos (u) + 78cos (3u) − 84cos (2u) + 84)/ρ β2,1 = 1 3 (16sin (3u) u 3 + 81sin (2u) u3 + 6u4 − 54cos (u) u2 + 78cos (3u) u2 + 144cos (2u) u2 + 150sin (u) u −102sin (3u) u − 120sin (2u) u + 12u2 + 57cos (u) + 57cos (3u) + 24cos (2u) − 24)/ρ β3,1 = 1 3 (−11sin (u) u 3 − 11sin (3u) u3 − 44sin (2u) u3 + 6u4 + 21cos (u) u2 − 45cos (3u) u2 − 48cos (2u) u2 +12sin (u) u + 36sin (3u) u + 12sin (2u) u + 36cos(2u) + 12u2 + 57cos (u) + 57cos (3u) + 24cos (2u) − 24)/ρ δ3,1 = ( ( −24u3 − 48 ) cos(2u) + ( −6u2 + 33 ) cos (3u) − 6cos (u) u2 − 71sin (u) u + 28sin (2u) u + 29sin (3u) u −33cos (u) + 48)/ρ γ3,1 = (29 sin (3 u) u + 28 u sin (2 u) − 6 u2 cos (u) − 24 cos (2 u) u2 − 6 cos (3 u) u2 − 71 sin (u) u − 33 cos (u) − 48 cos (2 u) +33 cos (3 u) + 48)/( ( −6 u3 + 21 u ) sin (3 u) + 18 (−cos (3 u) u + ( 3/2 u2 − 173 ) sin (2 u) + u3 − 3 u2 sin (u) −5 u cos (u) + 4 cos (2 u) u + 2 u + 47 sin(u)6 )u) (18)  β0,1 = − 121 405 − 289 42525 u 2 − 4397 53581500 u 4 + 518879123773265000 u 6 + 1540154587405481216140000 u 8 β1,1 = − 23 15 + 101 3150 u 2 + 18733969000 u 4 − 12401 833490000 u 6 − 48315783 300356456400000 u 8 β2,1 = 1 3 − 23 315 u 2 − 619 396900 u 4 + 5353916839000 u 6 + 7851770930035645640000 u 8 β3,1 = − 203 405 + 4061 85050 u 2 + 125353107163000 u 4 + 1200029247546530000 u 6 − 11234074463 8109624322800000 u 8 δ3,1 = 10 27 − 83 2835 u 2 − 3079 3572100 u 4 − 93587 8251551000 u 6 + 1115045320793908520000 u 8 γ3,1 = − 4 25 + 2 675 u 2 + 6112976750 u 4 + 548236876292500 u 6 + 45298619225267342300000 u 8 (19) 15 Abdulganiy et al. / J. Nig. Soc. Phys. Sci. 2 (2020) 12–25 16 β0,2 = 1 24 (44sin (u) u 3 + 17sin (2u) u3 − 6u4 + 60cos (u) u2 + 6cos (3u) u2 + 102cos (2u) u2 + 132sin (u) u −210sin (2u) u − 18u2 + 384cos (u) − 168cos (2u) − 216)/ρ β1,2 = 1 24 (−351sin (u) u 3 − 17sin (3u) u3 + 78u4 − 486cos (u) u2 − 54cos (3u) u2 − 216cos (2u) u2 − 18sin (u) +66sin (3u) u + 486sin (2u) u + 108u2 − 1248cos (u) + 600cos (2u) + 684)/ρ β2,2 = 1 24 ( ( −351u3 + 1278u ) sin(2u) + ( 44u3 − 102u ) sin (3u) − 78u4 + 432cos (u) u − 1134cos (2u) u2 +108cos (3u) u2 − 126u2 − 810sin (u) u + 384cos (u) + 246cos (2u) − 648)/ρ β3,2 = 1 24 (−125sin (u) u 3 + 13sin (3u) u3 − 152sin (2u) u3 − 6u4 + 138cos (u) u2 + 18cos (3u) u2 −444cos (2u) u2 + 204sin (u) u + 186sin (3u) u + 1248sin (2u) u − 168cos(2u) − 1080)/ρ δ3,2 = 1 4 (13sin (u) u 3 − sin (3u) u3 + 13sin (2u) u3 − 24cos (u) u2 + 24cos (2u) u2 − 87sin (u) u − 3sin (3u) u +48sin (2u) u − 288cos (u) + 72cos (2u) + 216/ρ γ3,2 = 1 24 (78cos (u) u 2 − 6cos (3u) u2 + 78cos (2u) u2 + 353sin (u) u + 13sin (3u) u − 340sin (2u) u − 6u2 +960cos (u) − 312cos (2u) − 648)/ρ (20)  β0,2 = 1 90 + 1 800 u 2 + 1571984500 u 4 + 1053089293388480000 u 6 + 1456666991201425825600000 u 8 β1,2 = − 61 160 − 331 67200 u 2 − 14369 42336000 u 4 − 6318043 391184640000 u 6 − 611857117 1067934067200000 u 8 β2,2 = −1 + 19 3360 u 2 + 6131058400 u 4 + 63165719559232000 u 6 + 672527513429840000 u 8 β3,2 = 533 1440 − 19 9600 u 2 − 40501 127008000 u 4 − 23157647 1173553920000 u 6 − 8248324979 961140660480000 u 8 δ3,2 = − 11 48 − 1 2240 u 2 + 5834233600 u 4 + 42094139118464000 u 6 + 169075937320380220160000 u 8 γ3,2 = 11 240 + 47 33600 u 2 + 70321168000 u 4 + 491195592320000 u 6 − 1081123 19776556800000 u 8 (21)  β0 = 1 24 (−20sin (u) u 3 + sin (2u) u3 − 6u4 − 132cos (u) u2 + 6cos (2u) u2 + 324sin (u) u − 18sin (2u) u − 18u2 +384cos(u) − 24cos (2u) − 360)/ρ β1 = 1 24 (81sin (u) u 3 − sin (2u) u3 + 30u4 + 522cos (u) u2 − 6cos (2u) u2 − 1218sin (u) u + 18sin (3u) u +6sin (2u) u + 60u2 − 1272cos (u) + 24cos (3u) − 24cos (2u) + 1272)/ρ β2 = 1 24 (20sin (u) u 3 − 81sin (2u) u3 − 114u4 − 432cos (u) u2 + 84cos (3u) u2 − 306cos (2u) u2 + 714sin (u) u −186sin (3u) u + 642sin (2u) u − 66u2 − 192cos (u) − 192cos (3u) + 840cos (2u) − 456)/ρ β3 = 1 24 (371sin (u) u 3 + 29sin (3u) u3 + 136sin(2u)u3 − 54u4 + 762cos (u) u2 + 66cos (3u) u2 − 276cos (2u) u2 −948sin (u) u + 186sin (2u) − 264u2 + 1080cos (u) + 168cos (3u) − 792cos (2u) − 456)/ρ δ3 = 1 4 (−19sin (u) u 3 − sin (3u) u3 + 5sin (2u) u3 − 24cos (u) u2 − 31sin (u) u − 11sin (3u) + 32sin (2u) + 24u2 −264cos (u) − 24cos (3u) + 120cos (2u) + 168)/ρ γ3 = 1 144 (116sin(2u) + ( 6u2 − 48 ) cos (3u) + 114cos(u)u2 − 30cos (2u) u2 + 54u2 − 433sin (u) u − 29sin (3u) u −912cos (u) + 264cos (2u) + 696)/ρ (22)  β0 = 1 810 + 229 1360800 u 2 + 35326790750 u 4 + 60449877921488960000 u 6 + 114774361732438497291200000 u 8 β1 = − 7 480 − 97 201600 u 2 − 6403 127008000 u 4 − 3738641 1173553920000 u 6 − 1490068837 9611406604800000 u 8 β2 = 1 3 − 1 1440 u 2 + 1513175200 u 4 + 2864595867769000 u 6 + 1711626160071291280000 u 8 β3 = 8813 12960 + 5483 5443200 u 2 − 35383 3429216000 u 4 − 77924501 31685955840000 u 6 − 42892337857 259507978329600000 u 8 δ3 = − 83 432 − 209 181440 u 2 − 1571 114307200 u 4 + 8447031056198528000 u 6 + 7008125718650265944320000 u 8 γ3 = 17 720 + 167 302400 u 2 + 3383190512000 u 4 + 8740511760330880000 u 6 + 12076795714417109907200000 u 8 (23) 16 Abdulganiy et al. / J. Nig. Soc. Phys. Sci. 2 (2020) 12–25 17 where ρ = u(18u2sin(u) + 2sin(3u)u2 − 9u2sin (2u) −6u3 + 30ucos (u) + 6cos (3u) u − 24cos (2u) u −47sin (u) − 7sin (3u) + 34sin(2u) − 12u) (24) It is interesting to note that as u → 0 in the power series expansion of the BTDTFMs, classical third derivative methods based on polynomial basis are recovered. 3. Basic Properties of BTDTFM The basic properties of BTDTFM which includes the Local Truncation Error (LTE), Order, Error Constant, Zero Stability, Convergence and Region of Stability are discussed. 3.1. Local Truncation Error (LTE) and Order of BTDTFM Theorem 1. The BTDTFM has a local truncation error of the form LT E = Ck+4hk+4(ω2yk+2(xn) − y(k+4)(xn)) + O(hk+5). Proof 1 Since the BTDTFM is made up of generalized linear multistep methods with trigonometric coefficients, we associate the BT- DTFM with a linear operator Lω [ y (xn) ; h ] for the principal method and Lω [ y (xn) ; h ] for the secondary methods defined respectively by  Lω [ y (xn) ; h ] = y (xn + kh) − ( yn+k−1 + h ∑k j=0 β j (u)y ′ (xn + kh) +h2δky ′′ (xn + kh) + h3γky ′′′ (xn + kh) Lω [ y (xn) ; h ] = y (xn + ih) − ( yn+k−1 + h ∑k j=0 β j (u)y ′ (xn + kh) +h2δk(u)y ′′ (xn + kh) + h3γk(u)y ′′′ (xn + kh) (25) Assuming that y(xn) is sufficiently differentiable, expanding with Taylor series expansions of y(xn +kh), y(xn +ih), y′(xn +kh), y′′(xn + kh) and y′′′(xn + kh) about the point xn. Substituting the coefficients β j (u) ,δk (u) ,γk (u) ,β j (u) δk(u) and γk(u) into equations (7) and (8) respectively, after simplifica- tion, we obtain the order, the Local Truncation Error as pre- sented in Table 1. � 3.2. Consistency of the BTDTFMs Since each BTDTFM is of order p ≥ 5 > 1, (for each k )as shown in Table 1, then it is consistent (Lambert [57] and Fatunla [58]). 3.3. Stability of the BTDTFM The combined methods (Principal and Secondary) are assemble in the block form given by A1Yµ+1 = A0Yµ+hB0 Fµ+hB1 Fµ+1+h 2Gµ+1C1+h 3 D1 Lµ+1(26) Where Yµ+1= (yn+1, yn+2, yn+3) T , Yµ = (yn−2, yn−1, yn) T , Fµ+1 = ( fn+1, fn+2, fn+3) T , Fµ = ( fn−2, fn−1, fn) T , Gµ+1 = (gn+1, gn+2, gn+3) T , Lµ+1 = (ln+1, ln+2, ln+3) T . A0, A1, B0, B1, C1 and D1 are k×k matrices defined in canonical form as follows: For k= 2, we have A1= ( −1 0 −1 1 ) , A0= ( 0 −1 0 0 ) , B0= ( 0 β0,0 0 β0 ) , B1= ( β1,0 β2,0 β1 β2 ) , C1= ( 0 δ2,0 0 δ2 ) and D1= ( 0 γ2,0 0 γ2 ) For k = 3, we have A1 =  1 −1 0 0 −1 0 0 −1 1  , A0 =  0 0 0 0 0 −1 0 0 0  , B0 =  0 0 β0,1 0 0 β0,0 0 0 β0  , B1 =  β1,1 β2,1 β3,1 β1,0 β2,0 β3,0 β1 β2 β3  , C1 =  0 0 δ3,1 0 0 δ3,0 0 0 δ3  and D1 =  0 0 γ3,1 0 0 γ3,0 0 0 γ3  3.4. Zero Stability Definition 2. A block method is zero stable if the roots of the first characteristic polynomial have modulus less than or equal to one and those of modulus one do not have multiplicity greater than 2. i.e. ρ(R) = det(RA(1) − A(0)) = 0 satisfies |Ri| ≤ 1 and for those roots with |Ri| = 1, the multiplicity does not exceed 2 Fatunla [58]. Proposition 3. The BTDTFM is zero stable. Proof 2 From the normalized first characteristic polynomial of BTDTFM, we have in canonical form that ρk (R) = det [∑1 i=0 A1−iR i ] . so that ρk (R) = 0 =⇒ −Rk−1 (1 + R) = 0. Consequently, the roots R j, j = 1, 2, . . . k of ρk(R) satisfy ∣∣∣R j∣∣∣ = 1, the roots are simple. Hence for each k = 2 and k = 3, the BTDTFM is Zero stable � 17 Abdulganiy et al. / J. Nig. Soc. Phys. Sci. 2 (2020) 12–25 18 Table 1: Local Truncation Error of BTDTFM k LTE Order ( p) Error Constant (C p+1) 2  ( − 1 1800 D (6) (y) (x) − 11800 ω 2 D(4) (y)(x) ) h6( − 1 200 D (6) (y) (x) − 1200 ω 2 D(4) (y)(x) ) h6  [ 5 5 ] − 1 1800 − 1 200 3  ( − 11 50400 D (7) (y) (x) − 1150400 ω 2 D(5) (y)(x) ) h7( 29 6300 D (7) (y) (x) + 296300 ω 2 D(5) (y)(x) ) h7( − 59 50400 D (7) (y) (x) − 5950400 ω 2 D(5) (y)(x) ) h7   6 6 6  − 1150400 296300 − 5950400 3.5. Convergence of BTDTFM Theorem 4. Let Y be an approximation of the solution vector Y for the system obtained from BTDTFM given by equations (6) and (7) respectively, If en = |y (xn) − yn|, where the exact solution is several times differentiable on [x0, xN ] and if ‖E‖ =∥∥∥Y − Y∥∥∥, then for sufficiently small h,BTDTFM is a (k + 3)th- order convergent method. That is ‖E‖ = O(hk+3). Proof 3 The proof can be readily obtained, similarly to the one given in Abdulganiy et al. (2017). � 3.6. Linear Stability and Region of Absolute Stability of BT- DTFM According to Ndukum et al. [47], linear stability analysis of trigonometrically fitted methods is more complicated than those of the corresponding polynomial-based methods for which λandh occur only in the combination z = λh . For trigonometrically fitted methods, three parameters are considered since the step length occurs in both z = λh and u = ωh . To analyze the linear stability of BTDTFM, the block method (25) is applied to the test equations y ′ = λy , y ′′ = λ2y and y ′′′ = λ3y . After simple algebraic simplification and letting z = λh , we obtain Yw+1 = M(z, u)Yw where M (z, u) = [ A1 − B1z − C1z 2 − D1z 3 ]−1 [A0 + B0z)] (27) The rational function M (z, u) is called the amplification matrix which determines the stability of the method. Definition (Coleman and Ixaru, [59]: A region of stability is a region in the zu−plane throughout which |ρ (z, u)| ≤ 1, where ρ (z, u) is the spectral radius of M (z, u). Since the stability matrix depends on two parameters z and u, we plot the stability regions in the (z, u)−plane for both k = 2 and k = 3 respectively in Figures 1 and 2. Definition (Ndukum etal., [47]): A BTDTFM with variable coefficients (A0 (u) , A1 (u) , B0 (u) , B1(u), C1(u), D1(u)) with the stability function ρ (z, u) is said to be A-stable at u = u0 if |ρ (z, u0)| < 1 for all z ∈ C−. We plot the region |ρ (z, u)| < 1 (for each k) in the complex plane via boundary locus method and look for the interval of Figure 1: The z − u Plot for BTDTFM k = 2 Figure 2: The z − u Plot for BTDTFM k = 3 u for which z ∈ C−. For k = 2, we notice that the values of u ∈ [2π,∞) are satisfactory and for k = 3, the values of u ∈ [2.96π, 2.70π] are satisfactory. Figures 3 and 4 show the plot of |ρ (z, u)| < 1 at u0 = 2π for k = 2 and u0 = 2.96π for k = 3 respectively. It is also worthy to note that the stability function of the BT- DTFM for each k satisfies |ρ (z, u)| < 1 for all z ∈ C−, for some u and limz→∞ ρ (z, u) = 0 is a property analogous to L−stability for the classical methods which is essential for a method to per- form well on highly stiff problems (Ndukum etal., [47]). Hence the BTDTFMs are L−stable. 18 Abdulganiy et al. / J. Nig. Soc. Phys. Sci. 2 (2020) 12–25 19 Figure 3: RAS for BTDTFM k = 2 Figure 4: RAS for BTDTFM k = 3 4. Estimation of Computational Frequency In fitted methods for solving periodic problems, the choice of estimating computational frequency remains a hard nut to crack. A rigorous theory for the exact computation of the fre- quency is yet to be developed. However, some attempts have been made by a number of researchers. For exponentially fit- ted methods, the procedure for estimating frequency is given in Ixaru et al. ([29], [60,61]), Vanden Berghe et al. ([30], [62,63]) and Van de Vyve.r [25]. The estimation of the computational frequency of trigonometrically-fitted methods can be found in Ramos and Vigo-Aguiar [64], Vigo-Aguiar and Ramos [65], Ngwane and Jator [42], Jator [48,49] and Ndukum et al., [47]. It is interesting to note that all the aforementioned methods fo- cus on the optimization of the local truncation error (LTE). In the present study, the approach described in Vanden Berghe et al. [30] for the exponentially fitted methods is adapted to the BTDTFM with Trigonometric coefficients. It is observed that the LTE of the principal and secondary methods of the BTDTFM consist of a product of three factors. The LTE of the principal method of k=2, for instance, consists of the product of a general factor, a numerical factor in rational form ( − 1 200 ) , and a factor which involves two derivatives of the solution vector. For easy reference, we introduce the follow- ing functional D [ y (x) ; ω ] = ( y(6) (x) + ω2y(4) (x) ) . Assume ω exists such that D is identically vanishes on the given interval, then the principal method corresponding to that ω will be exact. The reason according to Vanden Berghe et al. [30] is equiva- lent to solving the differential equation y(6) (x) + ω2y(4) (x) = 0 and, indeed, sin (ωx) and cos (ωx) are solutions. In general, no constant ω can be found such that D is identically vanished but it makes logic to discourse the problem of obtaining ω for which D are kept close to zero as possible for x in the given interval with the result that upon the Taylor series expansion of ω2 = − y(6) (xn ) y(4) (xn ) about xn given by D [ y (x) ; ω ] = − (x − xn) ( y(7) (xn) −ω2y(5) (xn) ) +O ( (x − xn) 2 ) . This implies that the bound of D behaves as h and conse- quently, the bound of LTE for k = 2 in Table 1 behaves as h7 and hence increase the order by 1. Remark 1. We remark that other steps and the technical de- tails for implementations are as described in section 3 of Var- den Berghe et al. [30]. 5. Numerical Experiments A number of numerical examples are provided in this sec- tion to illustrate the accuracy and computational efficiency of BTDTFM. We have calculated the absolute error at the end point for stiff problem as |y (t) − y| and the maximum abso- lute error of the approximate solution as Err = max |y (t) − y| for periodic problems and the efficiency is plotted as Number of Function Evaluation (NFE) against max |y (t) − y| . 5.1. Stiff Problems Example 5.1 We consider as our first example a non-linear system of first order differential equations in the range 0 ≤ t ≤ 10 y ′ 1 = µy1 + y 2 1 , y1 (0) = − 1 µ + 2 y ′ 2 = −y2 , y2 (0) = 1 whose solution in closed form is given by y1 = − e−2t µ+2 , y2 = e−2t , where µ = 10000 . The new BTDTFM is used to solve this problem with ω = 1 and compared with the Second Derivative Multistep Method (SDMM) in Hojjati et al. [7], Simpson’s 38 Method ( S 3 8 ) in Akinfenwa et al. [16], Multiderivative Hybrid Implicit Runge- Kutta Method (MHIRK) in Akinfenwa et al. [13], L stable Method (LM) in Mehdizabeh and Molayi [14], Third deriva- tive block hybrid method (TDBHM) in Akinfenwa [50] and the 19 Abdulganiy et al. / J. Nig. Soc. Phys. Sci. 2 (2020) 12–25 20 Figure 5: Numerical solution of Example 5.1 for h = 0.1 results are displayed in Table 2 for the accuracy while Figure 5 show the numerical solution of BTDTFM against the time t for h = 0.1 and ω = 1 . It is evident from Table 2 that the newly constructed method is more accurate than some of the previously known method in the literature. In particular, BTDTFM k = 2 is far more accurate with large step size compare to SSDM with smaller step size and compete favorably with S 3 8 with same step size, notwithstanding S 3 8 is of order 8. Example 5.2 Consider the non-linear stiff system given by y ′ 1 (t) = −1002y1 + 1000y 2 2 , y1 (0) = 1 y ′ 2 (t) = y1 − y2 (1 + y2) , y2 (0) = 1 Whose exact solution is given as y1 (t) = y22 , y2 (t) = e −t We solved this problem with ω = 1 . The results of BT- DTFM k = 2 for this problem in comparison with Exponen- tially fitted Gauss (EF-Gauss), Gauss-2s ,methods in Vaquero and Vigo-Aguiar [18] and Hybrid Backward differentiation for- mula (HBDF) of Jator and Agyingi [46] for h = 0.1 and h = 0.01 are displayed in Table 3. Table 4 presents the results of BT- DTFM k = 2 for different values of h as compared to Extended Continuous Block Backward Differentiation Formula (ECBBDF) of Akinfenwa and Jator [12] and Continuous Block Backward Differentiation Formula (CBBDF) of Akinfenwa et al. [11] for 0 ≤ t ≤ 10 while Table 5 shows the results of comparison with the LM method in Mehdizabeh and Molayi [14] and the method in Wu [6] for h = 0.05 in the interval 0 ≤ t ≤ 50 respec- tively. The graphical representation of the numerical results of BTDTFM at h = 0.05 is displayed in Figure 6. It is seen from Tables 3-5 that for various values of h con- sidered, BTDTFM does better in terms of accuracy than the methods in [18], [46], [12], [11], [14] and [6] respectively. Figure 6: Numerical solution of Example 5.2 for h = 0.05 Example 5.3 Consider a classical four-dimensional problem given by y′1 (t) y′2 (t) y′3 (t) y′4 (t)  =  −104y1 (t) + 100y2 (t) − 10y3 (t) + y4 (t) −1000y2 (t) + 10y3 (t) − 10y4 (t) −y3 (t) + 10y4 (t) −0.1y4 (t)  ,  y1 (0) y2 (0) y3 (0) y4 (0)  = 1 1 1 1  The eigenvalue of the Jacobian matrix λ1 = −0.1, λ2 = −1.0, λ3 = −1000 andλ4 = −10000 . The exact solution of Example 5.3 is given as y1 (t) = − 89990090 8999010009 e−0.1t + 818090 89901009 e−t + 9989911 899010090 e−1000t + 89071119179 89990100090 e−10000t y2 (t) = 9100 89991 e−0.1t − 910 8991 e−t + 9989911 9989001 e−1000t, y3 (t) = 100 9 e−0.1t − 91 9 e−t, y4 (t) = e −1.0t This problem is considered to show the performance of BT- DTFM on a 4 × 4 stiff problems. Table 6 shows the numerical results of BTDTFM with ω = 1 in comparison with the Second Derivative Extended Back- ward Differentiation Formula (SDEBDF) of Ehigie et al. [21] and the method NMTD in Adesanya et al. [22] for h = 0.05 and 0.1 at t = 20 while Table 7 displays the results BTDTFM as it compared with AB7 method in Abhulimen and Otunta [19], CEGE method of Abhulimen and Omeike [20] for h = 0.05 and 0.1 at t = 1 . The graphical representation of the numerical results of BTDTFM at h = 0.05 is shown in Figure 7. The results in Tables 6 and 7 showed the superiority of BT- DTFM in terms of accuracy over the methods it compared with 20 Abdulganiy et al. / J. Nig. Soc. Phys. Sci. 2 (2020) 12–25 21 Table 2: Comparison of results for Example 5.1 t h=0.0001 SSDM h=0.1 S 3 8 h=0.1 MHIRK h = 0.0001 LM h = 0.1 T DBH M h = 0.1 BT DT F Mk = 2 Err (y1) Err (y2) 3 2.48E-11 2.47E-06 2.03E-19 1.44E-14 3.06E-15 3.08E-10 1.78E-20 2.08E-12 1.34E-17 2.98E-13 6.54E-19 6.56E-14 Err (y1) Err (y2) 5 3.45E-14 2.30E-08 1.20E-20 3.21E-15 9.35E-17 6.94E-11 2.49E-19 4.66E-13 2.94E-18 1.79E-13 2.00E-20 1.48E-14 Err (y1) Err (y2) 10 3.46E-18 3.15E-11 1.11E-20 4.38E-17 8.49E-21 9.36E-13 5.74E-20 6.35E-12 3.82E-20 2.84E-14 1.81E-24 2.00E-16 Table 3: Comparison of errors at t = 5 for Example 5.2 h Gauss-2s EF-Gauss HBDF BTDTFM k = 2 0.1 5.12E − 06 8.36E − 07 5.49E − 11 1.82E − 11 0.01 6.46E − 12 4.24E − 12 6.07E − 15 2.01E − 16 Table 4: Comparison of methods at t = 10 for Example 5.2 h y C BBDF4 C BBDF5 EC BBDF4 EC BBDF5 BTDTFM k = 2 0.02 y1 y2 4.88E-16 5.39E − 12 8.37E-18 9.16E − 14 2.48E-19 3.75E − 16 1.33E-20 1.35E − 16 5.76E-19 6.34E − 15 0.01 y1 y2 3.13E-17 3.45E − 13 3.39E-21 1.23E − 17 2.68E-19 2.93E − 15 2.87E-22 2.93E − 15 1.82E-20 2.00E − 16 Table 5: Comparison of result of at t = 50 for Example 5.2 h y LMM WU Method BTDTFM k = 2 0.05 y1 y2 4.13E − 25 1.29E − 22 2.3E − 21 1.4E − 18 4.89E − 51 1.27E − 29 Table 6: Results comparison at t = 20 for Example 5.3 h Method y1 − Error y2 − Error y3 − Error y4 − Error 0.05 S DE BDF N MT D BT DT F M k = 2 5.31E-12 − 3.71 × E − 17 7.27E-11 − 3.75E − 16 5.90E-09 − 4.13E − 17 1.34E-09 − 3.41E − 15 0.1 DE BDF N MT D BTDTFM k = 2 2.25E-10 8.96E-07 1.18E − 15 2.29E-09 2.06E-08 1.19E − 10 2.50E-07 8.96E-10 1.31E − 12 2.06E-08 8.06E-11 1.19E − 13 in the reviewed literature. 5.2. Problems with Periodic Solutions Example 5.4 We consider the following system of couple differential equa- tions which is well known as the two body problem y ′′ 1 (t) = − y1 r3 , y1 (0) = 1, y ′ 1 (0) = 0 y ′′ 2 (t) = − y2 r3 , y2 (0) = 0, y ′ 2 (0) = 0 21 Abdulganiy et al. / J. Nig. Soc. Phys. Sci. 2 (2020) 12–25 22 Table 7: Results comparison at t = 1 for Example 5.3 h Method y1 − Error y2 − Error y3 − Error y4 − Error 0.05 AB7 CEGE N MT D BT DT F M k = 2 3.2E-02 3.5E-05 7.5E-11 2.2E − 12 3.2E-02 3.8E-04 8.6E-10 2.5E − 12 3.3E-01 3.5E-07 8.3E-08 2.5E − 09 3.7E-05 3.7E-08 2.9E-09 1.3E − 11 0.1 AB7 CEGE N MT D BTDTFM k = 2 2.5E-02 2.9E-05 1.4E-08 6.7E − 11 2.1E-01 2.7E-04 1.3E-08 7.5E − 10 2.4E-03 2.6E-06 2.1E-09 7.5E − 08 2.7E-05 2.6E-08 2.7E-11 4.0E − 14 Figure 7: Numerical solution of Example 5.3 for h = 0.05 where r = √ y21 + y 2 2 and whose analytic solution is given by y1 (t) = cos (t) , y2 (t) = sin (t) The problem was considered in Senu et al. [36] and Abdul- ganiy et al. [44] in the interval 0 ≤ t ≤ 10 with ω = 1. The BTDTFM is compared with Block Hybrid Trigonometry Method (BHTM) of Abdulganiy et al. [44] and a New Diago- nally Implicit Runge-Kutta Nystrom Method for Periodic IVPs (DIRKNNew) of Senu et al. [36] and the numerical results are displayed in Table 8 below. While the graphical illustration of BTDTFM is shown in Figure 8, Figure 9 shows the efficiency of BTDTFM. It is evident from Table 8 that the newly devel- oped method BTDTFM uses fewer number of function evalua- tion and consequently produces good results and gives a better approximation when compared with BHTM and DIRKNNew. Also, Figure 9 hows that the method in this paper is efficient. Example 5.5: Nonlinear Strehmel-Weiner problem We consider the nonlinear second order IVP which was also solved by Nguyen et al. [35] and Jator [37] in the interval 0 ≤ t ≤ 10 respectively y”1 (t) = (y1 (t) − y2 (t)) 3 + 6368y1 Figure 8: Numerical solution of Example 5.4 Figure 9: Efficiency Curve of Example 5.4 × (t) − 6384y2 (t) + 42 cos (10t) , y1 (0) = 0.5, y ′ 1 (0) = 0 y”1 (t) = − (y1 (t) − y2 (t)) 3 + 12768y1 (t) − 12784y2 (t) +42 cos (10t) , y2 (0) = 0.5, y ′ 2 (0) = 0 with analytic solution in closed form given by y1 (t) = y2 (t) = cos (4t) − cos(10t)2 . Numerical results of the maximum global errors of BTDTFM 22 Abdulganiy et al. / J. Nig. Soc. Phys. Sci. 2 (2020) 12–25 23 Table 8: Comparison of Numerical Results for Example 5.4 N BTDTFM k = 2 BHTM DIRKNNew Error NFE Error NFE Error NFE 100 2.84E − 29 201 5.13E − 27 1600 7.49 E − 4 5000 200 1.92E − 28 401 1.30E − 29 3200 5.62E − 7 10000 400 1.18E − 27 801 4.0E − 30 6400 1.00E − 9 25000 800 2.47E − 27 1601 7.43E − 28 12800 1.78E − 7 60000 Table 9: Comparison of Maximum Errors and Number of Function Evaluation BTDTFM k = 2 SVBM TIRKN 3 N F E Err N F E Err N F E Err 751 2.25E-7 801 2.6E-7 907 2.5E-4 1126 2.95E-8 1201 1.6E-8 1288 6.6E-6 1501 7.01E-9 1601 2.8E-9 1682 7.0E-6 Table 10: Comparison of Number of steps used in the computation for ω = 10 Steps BTDTFM k = 2 Err Vigo-Aguiar and Ramos Err NEWS5(4)-2 Err 898 5.5 2.5 4.9 1344 6.6 3.2 6.5 2123 7.8 3.4 7.8 2990 8.7 4.6 8.9 4690 9.9 5.3 9.9 7215 11.0 6.1 11.0 k = 2 were compared with Symmetric Boundary Value Method (SBVM) of Jator [37] and Trigonometric Implicit Runge-Kutta Methods (TIRKM) of Nguyen [35] are presented in Table 9 while Figure 10 is the graphical representation of the numerical results of BTDTFM. Also, Figure 11 shows that the method in this paper is more efficient In Table 9 and Figure 11, we show that a fifth order BT- DTFM has almost the same maximum errors with SVBM of order 6 but uses fewer number of function evaluation and con- sequently a more accurate and more efficient integrator for the nonlinear Strehmel-Weiner problem. Example 5.6: A Nonlinear Oscillator Lastly, we consider the initial-value problem ẍ = −100x + sin (x) , x (0) = 0, ẋ (0) = 1, t ∈ [0, 20π] The analytical solution is not known but for comparison purposes we use that x (20π) = 0.000392823991 given by Tsi- touras and Simos [34]. The comparison of different number of steps of BTDTFM k = 2 with NEW5(4)-2 of Tsitouras and Simos [34] and method in Vigo-Aguiar and Ramos [65] with ω = 10. The number of steps are obtained as contained in the references from literature. The error is calculated as Err = Figure 10: Numerical solution of Example 5.5 −log ( |x ( t f − x f ) | ) where x f is the approximation value ob- tained at the final point t f . Table 10 revealed that BTDTFM compete favourably with methods in Tsitouras and Simos [34] and method in Vigo-Aguiar and Ramos [65]. 23 Abdulganiy et al. / J. Nig. Soc. Phys. Sci. 2 (2020) 12–25 24 Figure 11: Efficiency Curve of Example 5.5 Figure 12: Numerical solution of Example 5.6 6. Conclusion A family of order k+3 Block Third Derivative Trigonometrically- Fitted Methods are considered and implemented in this paper for Stiff and Periodic Problems. The stability properties of the method was analyzed and was found to be L-stable which in fact is a requirement for an algorithm to solving stiff problems. 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