5
Periodic Solutions for P -Laplacian Differential Equation with Singular Forces of Attractive Type De-xin Lan and Wen-bin Chen * Abstract—This paper is concerned with the periodic solutions for p-Laplacian differential equation with singular forces of attractive type. By employing Mawhin’s coincidence degree theorem and some analytical techniques, some new results on the existence of periodic solutions are derived. The numerical results demonstrate the remarkable accuracy and efficiency of our method compared with other schemes. Index Terms—Periodic solution, p-Laplacian equation, Con- tinuation theorem, Singular forces. I. I NTRODUCTION T HE aim of this paper is to consider the solvability of periodic boundary value problem for p-Laplacian differential equation with singular forces of attractive type as follows (ϕ p (x 0 (t))) 0 + f (x 0 (t)) + g(t, x(t)) = e(t), (1) x(0) = x(T ),x 0 (0) = x 0 (T ), (2) where ϕ p (s)= |s| p-2 s with p> 1, f : R × R R is continuous, g : R × (0, +) R is an L 2 -Cauath´ eodory function, g(t, x) is T -periodic with the first variable and can be singular at x =0, i.e., g(t, x) can be unbounded as x 0 + . The problem (1)-(2) is of attractive type if g(t, x) +for x 0 + . In the past few years, there were plenty of results on the existence of periodic solutions of Duffing, Li ´ enard or Rayleigh type equation with a singularity, (see [1-8, 11-15] and the references therein). For example, recently, Zhang [3] studied the following Li ´ enard equation with singular forces of repulsive type: x 00 (t)+ f (x(t))x 0 (t)+ g(t, x(t)) = 0, (3) where f : R × R R is continuous, g : R × (0, +) R is an L 2 -Cauath´ eodory function, g(t, x) is T -periodic with the first variable and can be singular at x =0, i.e., g(t, x) can be unbounded as x 0 + . Equation (3) is repulsive type if g(t, x) → -∞ for x 0 + . Meanwhile, let ¯ g(x)= 1 T Z T 0 g(t, x) dt, x > 0. Assume that ϕ(t) = lim sup x+g(t, x) x Manuscript received June 28, 2017; revised September 01, 2017. This work was supported by Natural Science Foundation of Fujian Provin- cial(NO. 2015J01669) and Fujian Province Young-Middle-Aged Teachers Education Scientific Research Project (No. JA15524). * Wen-bin Chen, Corresponding Author, is with the Department of Mathematics and Computer, Wuyi University, Wuyi Shan 354300, China and Computer and the key laboratory of cognitive computing and in- telligent information processing of Fujian Education Institutions (E-mail: [email protected]). De-xin Lan is with the Department of of Mathematics and Computer, Wuyi University, Wuyi Shan, Fujian, 354300, China. exists uniformly a.e. for t [0,T ]. Where ϕ C(R, R) and ϕ(t + T )= ϕ(t), t R. Assume that the following conditions are satisfied. (H 1 ) (Balance condition) There exist constants 0 <D 1 < D 2 such that if x is a positive continuous T -periodic function satisfying 1 T Z T 0 g(t, x(t)) dt =0, then D 1 x(τ ) D 2 , for some τ [0,T ]. (H 2 ) (Degree condition) ¯ g(x) < 0 for all x (0,D 1 ), and ¯ g(x) > 0 for all x>D 2 . (H 3 ) (Decomposition condition) g(t, x)= g 0 (x)+ g 1 (t, x), where g 0 C((0, +),R) and g 1 : [0,T ] × [0, +) R is an L 2 -Carath´ eodory function, i.e., g 1 is measurable with respect to the first variable, continuous with respect to the second one, and for any b > 0 there is h b L 2 ((0,T ); [0, +)) such that |g 1 (t, x)|≤ h b (t) for a.e. t [0,T ] and all x [0,b]. (H 4 )(Strong force condition at x =0) R 1 0 g 0 (x) dx = -∞. (H 5 )(Small force condition at x = ) ||ϕ + || 1 < 3 T , (ϕ + (t) = max(ϕ(t), 0)). In [3], the following theorem was proved. Theorem 1. Assume that the conditions (H 1 ) - (H 5 ) are satisfied. Then Eq. (3) has at least one positive T -periodic solution. On the basis of work of Zhang, Wang [4] further studied periodic solutions for the Li ´ enard equation with a singular- ity and a deviating argument, which is different from the literature [2], x 00 (t)+ f (x(t))x 0 (t)+ g(t, x(t - σ)) = 0, (4) where 0 σ<T is a constant, f : R × R R is continuous, g : R × (0, +) R is an L 2 -Cauath´ eodory function, g(t, x) is T -periodic with the first variable and can be singular at x =0, i.e., g(t, x) can be unbounded as x 0 + . Eq. (4) is repulsive type if g(t, x) → -∞ for x 0 + . By using Mawhin’s continuation theorem, the authors proved the following theorem. Theorem 2. Assume that the conditions (H 1 ) - (H 4 ) are satisfied. If further assumed: (H 0 5 ) (Small force condition at x = ) ||ϕ|| < π T 2 . Then Eq.(4) has at least one positive T -periodic solution. IAENG International Journal of Applied Mathematics, 48:1, IJAM_48_1_04 (Advance online publication: 10 February 2018) ______________________________________________________________________________________

Periodic Solutions for PLaplacian Differential Equation ... · +(9 + 0:5sin(1000t)) 1 x17(t) = sin(1000t): (7) By Theorem 3 and (1), we have f(x) = x3, g(t;x(t)) = 1 2 1x(t) + (9

  • Upload
    others

  • View
    1

  • Download
    0

Embed Size (px)

Citation preview

  • Periodic Solutions for P−Laplacian DifferentialEquation with Singular Forces of Attractive Type

    De-xin Lan and Wen-bin Chen∗

    Abstract—This paper is concerned with the periodic solutionsfor p−Laplacian differential equation with singular forces ofattractive type. By employing Mawhin’s coincidence degreetheorem and some analytical techniques, some new results onthe existence of periodic solutions are derived. The numericalresults demonstrate the remarkable accuracy and efficiency ofour method compared with other schemes.

    Index Terms—Periodic solution, p−Laplacian equation, Con-tinuation theorem, Singular forces.

    I. INTRODUCTION

    THE aim of this paper is to consider the solvabilityof periodic boundary value problem for p−Laplaciandifferential equation with singular forces of attractive typeas follows

    (ϕp(x′(t)))′ + f(x′(t)) + g(t, x(t)) = e(t), (1)

    x(0) = x(T ), x′(0) = x′(T ), (2)

    where ϕp(s) = |s|p−2s with p > 1, f : R × R → R iscontinuous, g : R × (0,+∞) → R is an L2−Cauathéodoryfunction, g(t, x) is T−periodic with the first variable and canbe singular at x = 0, i.e., g(t, x) can be unbounded as x→0+. The problem (1)-(2) is of attractive type if g(t, x)→ +∞for x→ 0+.

    In the past few years, there were plenty of results onthe existence of periodic solutions of Duffing, Liénard orRayleigh type equation with a singularity, (see [1-8, 11-15]and the references therein). For example, recently, Zhang [3]studied the following Liénard equation with singular forcesof repulsive type:

    x′′(t) + f(x(t))x′(t) + g(t, x(t)) = 0, (3)

    where f : R×R→ R is continuous, g : R× (0,+∞)→ Ris an L2−Cauathéodory function, g(t, x) is T−periodic withthe first variable and can be singular at x = 0, i.e., g(t, x)can be unbounded as x→ 0+. Equation (3) is repulsive typeif g(t, x)→ −∞ for x→ 0+. Meanwhile, let

    ḡ(x) =1

    T

    ∫ T0

    g(t, x) dt, x > 0.

    Assume that

    ϕ(t) = lim supx→+∞

    g(t, x)

    x

    Manuscript received June 28, 2017; revised September 01, 2017. Thiswork was supported by Natural Science Foundation of Fujian Provin-cial(NO. 2015J01669) and Fujian Province Young-Middle-Aged TeachersEducation Scientific Research Project (No. JA15524).∗Wen-bin Chen, Corresponding Author, is with the Department of

    Mathematics and Computer, Wuyi University, Wuyi Shan 354300, Chinaand Computer and the key laboratory of cognitive computing and in-telligent information processing of Fujian Education Institutions (E-mail:[email protected]).

    De-xin Lan is with the Department of of Mathematics and Computer,Wuyi University, Wuyi Shan, Fujian, 354300, China.

    exists uniformly a.e. for t ∈ [0, T ]. Where ϕ ∈ C(R, R)and ϕ(t+ T ) = ϕ(t), ∀t ∈ R.

    Assume that the following conditions are satisfied.(H1) (Balance condition) There exist constants 0 < D1 <D2 such that if x is a positive continuous T−periodicfunction satisfying

    1

    T

    ∫ T0

    g(t, x(t)) dt = 0,

    thenD1 ≤ x(τ) ≤ D2,

    for some τ ∈ [0, T ].(H2) (Degree condition) ḡ(x) < 0 for all x ∈ (0, D1), andḡ(x) > 0 for all x > D2.(H3) (Decomposition condition) g(t, x) = g0(x) + g1(t, x),where g0 ∈ C((0,+∞), R) and g1 : [0, T ]× [0, +∞)→ Ris an L2−Carathéodory function, i.e., g1 is measurablewith respect to the first variable, continuous with respectto the second one, and for any b > 0 there is hb ∈L2((0, T ); [0, +∞)) such that |g1(t, x)| ≤ hb(t) for a.e.t ∈ [0, T ] and all x ∈ [0, b].(H4)(Strong force condition at x = 0)

    ∫ 10g0(x) dx = −∞.

    (H5)(Small force condition at x =∞)

    ||ϕ+||1 <√

    3

    T, (ϕ+(t) = max(ϕ(t), 0)).

    In [3], the following theorem was proved.

    Theorem 1. Assume that the conditions (H1)− (H5) aresatisfied. Then Eq. (3) has at least one positive T−periodicsolution.

    On the basis of work of Zhang, Wang [4] further studiedperiodic solutions for the Liénard equation with a singular-ity and a deviating argument, which is different from theliterature [2],

    x′′(t) + f(x(t))x′(t) + g(t, x(t− σ)) = 0, (4)

    where 0 ≤ σ < T is a constant, f : R × R → R iscontinuous, g : R × (0, +∞)→ R is an L2−Cauathéodoryfunction, g(t, x) is T−periodic with the first variable andcan be singular at x = 0, i.e., g(t, x) can be unboundedas x → 0+. Eq. (4) is repulsive type if g(t, x) → −∞for x → 0+. By using Mawhin’s continuation theorem, theauthors proved the following theorem.

    Theorem 2. Assume that the conditions (H1)− (H4) aresatisfied. If further assumed:(H ′5) (Small force condition at x =∞)

    ||ϕ||∞ <( πT

    )2.

    Then Eq.(4) has at least one positive T−periodic solution.

    IAENG International Journal of Applied Mathematics, 48:1, IJAM_48_1_04

    (Advance online publication: 10 February 2018)

    ______________________________________________________________________________________

  • Fig. 1: Numerical solutions for Eq. (6)

    Inspired by the above mentioned works, in this paper,we study the existence of positive periodic solution forp−Laplacian differential equation with singular forces ofattractive type. To the best of our knowledge, there are fewerpapers dealing with the periodic solutions for p−Laplaciandifferential equation with singular forces of attractive type inthe literature. By applying Mawhin’s continuation theorem,we prove the following theorem.

    Theorem 3. Assume that the following conditions aresatisfied:(h1) lim

    x→0inf

    t∈[0, T ]g(t, x) = +∞,

    (h2) There exist nonnegative constants m1, m2, f(0) = 0and α ≤ p− 1 such that

    |f(u)| ≤ m1|u|α +m2, ∀u ∈ R.

    (h3) There exist constants 0 < D̄1 < D̄2 such that g(t, u)−e(t) > 0, (t, u) ∈ [0, T ] × (0, D̄1], and g(t, u) − e(t) <0, (t, u) ∈ [0, T ]× [D̄2, ∞).Then the problem (1)-(2) has at least one positive T−periodicsolution.

    Remark 1. When p = 2, Eq. (1) reduces to the followingsecond-order differential equation

    x′′(t) + f(t, x′(t)) + g(t, x(t)) = 0. (5)

    We can construct concrete functions g and f such that allconditions of Theorem 3 are satisfied. For example, considerthe following equation

    x′′(t) + (x′(t))3 − 12

    (1 + 0.5 sin(1000t))1

    x3(t)= sin(100t).

    (6)Corresponding to Theorem 3 and (5), we have f(x) = x3,g(t, x(t)) = − 12 + (1 + 0.5 sin(1000t))

    1x3(t) , e(t) =

    sin(1000t), m1 = 1, α = 3, m2 = 12 , D̄1 = 0.1,D̄2 = 2. By using Theorem 3, Eq. (6) has at least onepositive T−periodic solution. It is not difficult to find thatthe singular item g0(x) do not include the independentvariables t in Eq. (3) and Eq. (4). But, the singular itemg(t, x) in Eq. (6) has the independent variables t. Thiscan also be illustrated by numerical simulation. By usingMATLAB (R2013a) toolkit: ode45. Eq. (6) is simulated ontspan=[90.06, 94.65] with history=[2, 2]. Fig.1 shows thatthe equation admits one positive T−periodic solution.

    Remark 2. When p 6= 2, We can consider the following

    Fig. 2: Numerical solutions for Eq. (7)

    equation

    (ϕ3(x′(t)))′ + (x′(t))3 − 1

    2− x(t)

    +(9 + 0.5 sin(1000t))1

    x17(t)= sin(1000t). (7)

    By Theorem 3 and (1), we have f(x) = x3, g(t, x(t)) =− 12 − x(t) + (9 + 0.5 sin(1000t))

    1x17(t) , e(t) = sin(1000t),

    m1 = 1, α = 3,m2 =12 , D̄1 =

    12 , D̄2 = 2. According to

    Theorem 3, Eq. (7) has at least one positive T−periodic so-lution. Similarly, Eq. (7) can also be illustrated by numericalsimulation, which is simulated on tspan=[421.7, 422.7] withhistory=[1.5, -1.5] see Fig. 2. Therefore, the results achievedin this paper are significant.

    The rest of the paper is organized as follows. In sectionII, some necessary definitions and Lemmas are introduced.In section III, the existence of positive periodic solutionsconditions are presented.

    II. PRELIMINARIES

    Lemma 1. [9] Let L be a Fredholm operator of indexzero and let N be L−compact on Ω̄. Suppose that thefollowing conditions are satisfied:(a1) Lx 6= λNx, ∀(x, λ) ∈ ∂Ω× (0, 1);(a2) QNv /∈ ImL, ∀x ∈ KerL ∩ ∂Ω;(a3) deg{JQN, Ω ∩ KerL, 0} 6= 0, where Q : Z → Z isa projection with ImL = KerQ, J : ImQ → KerL is aisomorphism with J(θ) = θ, where θ is the zero element ofZ.Then Lx = Nx has at least one solution in D(L) ∩ Ω̄.

    Lemma 2. [10] (Generalized Bellman’s Inequality). Con-sider the following inequality:

    |y(t)| ≤ C +M∫ t

    0

    |y(s)|β ds, (8)

    where C,M, β are nonnegative constants and t > 0. If β ≤ 1,then for t ∈ (0, T0], we have |y(s)| ≤ D, where

    D =

    {CeMT0 , if β = 1;(C1−β +MT0(1− β))

    11−β , if β < 1.

    In order to use Mawhin’s continuation theorem, we shouldconsider the following system:{

    x′(t) = ϕq(y(t)),y′(t) = −f(ϕq(y(t)))− g(t, x(t)) + e(t),

    (9)

    where ϕq(s) = |s|q−2s, 1p +1q = 1, y(t) = ϕp(x

    ′(t)).Obviously, if (x(t), y(t))> is a solution of (9), then x(t)is a solution of (1)-(2).

    IAENG International Journal of Applied Mathematics, 48:1, IJAM_48_1_04

    (Advance online publication: 10 February 2018)

    ______________________________________________________________________________________

  • Throughout this paper, let X = Y = {u = (x(t), y(t))> ∈C(R, R2), u(t) = u(t+T )}, where the norm |u|0 = max{|x |0, | y |0}, and | x |0= max

    t∈[0,T ]| x(t) |, | y |0= max

    t∈[0,T ]|

    y(t) |. It is obvious that X and Y are Banach spaces.Now we define the operator

    L : D(L) ⊂ X → Y,Lu = u′ = (x′(t), y′(t))>,

    where D(L) = {u|u = (x(t), y(t))> ∈ C1(R, R2), u(t) =u(t+ T )}.

    Let Z = {u|u = (x(t), y(t))> ∈ C1(R, R × Γ), u(t) =u(t+ T )}, where Γ = {x ∈ R, x(t) = x(t+ T )}. Define anonlinear operator N : Ω̄→ Y as follows:

    Nv = (ϕq(y(t)),−f(ϕq(y(t)))− g(t, x(t)) + e(t))> ,

    where Ω ⊂ (X ∩ Z) ⊂ X and Ω is an open and boundedset. Then problem (1)-(2) can be written as Lv = Nv in Ω̄.

    We know

    KerL = {u|u ∈ X,u′ = (x′(t), y′(t))> = (0, 0)>},

    then x′(t) = 0, y′(t) = 0. Obviously x ∈ R, y ∈ R, thusKerL = R2, and it is also easy to prove that ImL = {z ∈Y,∫ T

    0z(s)ds = 0}. So, L is a Fredholm operator of index

    zero.Let

    P : X → KerL, Pv = 1T

    ∫ T0

    v(s) ds,

    Q : Y → ImQ,Qz = 1T

    ∫ T0

    z(s) ds.

    Let Kp = L |−1Kerp∩D(L), then it is easy to see that

    (Kpz)(t) =

    ∫ T0

    G(t, s)z(s) ds,

    whereG(t, s) =

    {s−TT , 0 ≤ t ≤ s;sT , s ≤ t ≤ T .

    For all Ω such that Ω̄ ⊂ (X ∩ Z) ⊂ X , we have Kp(I −Q)N(Ω̄) is a relative compact set of X , QN(Ω̄) is a boundedset of Y . Thus the operator N is L-compact in Ω̄.

    III. PROOF OF THEOREM 3

    Firstly, let Ω1 = {x ∈ Ω, Lx = λNx,∀λ ∈ (0, 1)}. If∀λ ∈ Ω1, we have{

    x′(t) = λϕq(y(t)),y′(t) = −λf(ϕq(y(t)))− λg(t, x(t)) + λe(t).

    (10)By substituting y(t) = ϕp( 1λx

    ′(t)) into the second equationof (10), we have

    (ϕp(1

    λx′(t)))′+λf(

    1

    λx′(t))+λg(t, x(t)) = λe(t), λ ∈ (0, 1)

    (11)Let x(t) be an arbitrary T−periodic solution of (11). Assumethat

    x(t1) = maxt∈[0,T ]

    x(t), x(t2) = mint∈[0,T ]

    x(t), t1, t2 ∈ [0, T ].(12)

    Then we getx′(t1) = 0, x

    ′′(t1) ≤ 0. (13)

    x′(t2) = 0, x′′(t2) ≥ 0. (14)

    From (11), (14), and using (ϕp(x′(t)))′ = (p −1)|x′(t)|p−2x′′(t), we obtain

    g(t2, x(t2)) = −1

    λ(ϕp(

    1

    λx′(t2)))

    ′ + e(t) ≤ e(t).

    Then from the assumption (h3), we must have that thereexists D̄1 > 0 such that

    x(t2) > D̄1. (15)

    Similarly, substituting (11) and (13), we can see that thereexist positive D̄2 such that

    x(t1) < D̄2. (16)

    (15) and (16) implies that x(t) is bounded and

    D̄1 < x(t2) ≤ x(t) ≤ x(t1) < D̄2. (17)

    Next we show that y(t) is bounded. From the secondequation of (10) and x′(t1) = 0, hence y(t1) = 0. Thusfor any t ∈ [0, T ] such that 0 ≤ t1 ≤ t, by the assumption(h2), we can write

    |y(t)|

    =

    ∣∣∣∣y(t1) + ∫ tt1

    y′(s)ds

    ∣∣∣∣ = ∫ tt1

    |y′(s)|ds

    ≤∫ t

    0

    |y′(s)|ds

    ≤∫ t

    0

    | − λf(ϕq(y(s)))− λg(s, x(s)) + λe(s)|ds

    ≤∫ t

    0

    |f(ϕq(y(s)))|+ |g(s, x(s))− e(s)|ds

    ≤∫ t

    0

    |f(ϕq(y(s)))|ds+∫ T

    0

    |g(s, x(s))− e(s)|ds

    ≤ T maxt∈[0,T ],x∈(D̄1,D̄2)

    |g(t, x)− e(t)|

    +Tm2 +m1

    ∫ t0

    |y(s)|(q−1)αds. (18)

    Let D1 = T maxt∈[0,T ],x∈(D̄1,D̄2)

    |g(t, x)−e(t)| and β = (q−

    1)α = αp−1 . Then from (18) we get

    |y(t)| ≤ D1 +m1∫ t

    0

    |y(s)|βds.

    Note that 0 ≤ β ≤ 1 since 0 ≤ α ≤ p − 1 fromthe assumption (h3). Now from the generalized Bellman’sinequality (8), we obtain |y(t)| ≤ D2 for all t ∈ [t1, T ],where

    D2 =

    {D1e

    m1T , if α = p− 1;(D

    p−1−αp−1

    1 +m1T (p−1−α)

    p−1 )p−1

    p−1−α , if α < p− 1.

    If 0 ≤ t ≤ t1, we have 0 ≤ t1 ≤ t + T ≤ 2T and from the

    IAENG International Journal of Applied Mathematics, 48:1, IJAM_48_1_04

    (Advance online publication: 10 February 2018)

    ______________________________________________________________________________________

  • T−periodicity of y(t) and the assumption (h3), we have

    |y(t)|

    = |y(t+ T )| =∣∣∣∣y(t1) + ∫ t1

    t+T

    y′(s)ds

    ∣∣∣∣=

    ∣∣∣∣∫ t1t+T

    y′(s)ds

    ∣∣∣∣≤

    ∫ t+Tt1

    |y′(s)|ds

    ≤∫ t+T

    0

    |y′(s)|ds

    ≤∫ t+T

    0

    |λf(ϕq(y(s))) + λg(s, x(s))− e(s)|ds

    ≤∫ t+T

    0

    |f(ϕq(y(s)))|+ |g(s, x(s))− e(s)|ds

    ≤∫ t+T

    0

    |f(ϕq(y(s)))|ds+∫ 2T

    0

    |g(s, x(s))− e(s)|ds

    ≤ 2T maxt∈[0,T ],x∈(D̄1,D̄2)

    |g(t, x)− e(t)|+ 2Tm2

    +m1

    ∫ t+T0

    |y(s)|(q−1)αds. (19)

    From the above inequality, it follows that for 0 ≤ t ≤ t1,we have |y(t)| = |y(t + T )| ≤ 2D1 + m1

    ∫ t+T0|y(s)|βds.

    This implies that for 0 ≤ t ≤ t1, we have |y(t)| ≤ D3, where

    D3 =

    {2D1e

    m1T , if α = p− 1;(2D

    p−1−αp−1

    1 +2m1T (p−1−α)

    p−1 )p−1

    p−1−α , if α < p− 1.

    Since D2 ≤ D3, the above inequalities imply that

    |y|0 := maxt∈[0,T ]

    |y(t)| ≤ D3, (20)

    which again implies

    |x′|0 ≤ Dq−13 = D1p−13 . (21)

    Let Ω2 = {u : u ∈ kerL,QNu = 0}. If u ∈ R2 is aconstant vector with{

    |y(t)|q−2y(t) = 0,1T

    ∫ T0

    [−f(ϕq(y(t)))− g(t, x(t)) + e(t)]dt = 0.

    So y(t) = 0 and by assumption (h2), we can see that thereexist constants M1 > 0 and M2 > 0 such that

    M1 < x(t) < M2.

    Let us define 0 < A1 = min(M1, D̄1) and A2 =max(M2, D̄2), then

    A1 < x(t) < A2,

    which implies Ω2 ⊂ Ω1. Now, if we set Ω = {u : u =(x, y)> ∈ X,A1 < x < A2, |y|0 < D3 + 1}, then Ω ⊃Ω1⋃

    Ω2. So from (17) and (20), we see that conditions (a1)and (a2) of Lemma 1 are satisfied. The remainder is to verifycondition (a3) of Lemma 1. In order to do it, let

    z = Kx = K

    (xy

    )=

    (x− A1+A22

    y

    ),

    then, we have

    x = z +

    (A1+A2

    20

    ).

    Define J : ImQ→ KerL is a linear isomorphism with

    J(x, y) =

    (yx

    ),

    and define

    H(µ, u) = µKu+ (1− µ)JQNu, ∀(u, µ) ∈ Ω× [0, 1].

    Then,

    H(µ, u) =

    (µx− µ(A1+A2)2

    µy

    )+

    1− µT

    ·

    (∫ T0

    [−f(ϕq(y(t)))− g(t, x(t)) + e(t)]dt∫ T0ϕq(y(t))dt

    ). (22)

    Now we claim that H(µ, u) is a homotopic mapping. Byway of contradiction, assume that there exist µ0 ∈ [0, 1] andu0 =

    (x0y0

    )∈ ∂Ω such that H(µ0, u0) = 0.

    Substituting µ0 and u0 into (22), we have

    H(µ0, u0)

    =

    (µ0x0 − µ0(A1+A2)2 Φ

    µ0y0 + (1− µ0)ϕq(y0))

    ), (23)

    where Φ = −(1− µ0)f(ϕq(y0))− (1− µ0)[g(t, x0)− e(t)].Since H(µ0, x0) = 0, then we can see that

    µ0y0 + (1− µ0)ϕq(y0)) = 0.

    Combining with µ0 ∈ [0, 1], we obtain y0 = 0. Thus x0 =A1 or A2.

    If x0 = A1, it follows from (h2) that g(t, x0)− e(t) > 0,then substituting y0 = 0 into (23), we have

    µ0x0 −µ0(A1 +A2)

    2−(1− µ0)f(ϕq(y0))− (1− µ0)[g(t, x0)− e(t)]

    = µ0x0 −µ0(A1 +A2)

    2− (1− µ0)[g(t, x0)− e(t)]

    < µ0(x0 −(A1 +A2)

    2).

    < 0. (24)

    If x0 = A2, it follows from (h2) that g(t, x0)− e(t) < 0,then substituting y0 = 0 into (23), we have

    µ0x0 −µ0(A1 +A1)

    2−(1− µ0)f(ϕq(y0))− (1− µ0)[g(t, x0)− e(t)]

    = µ0x0 −µ0(A1 +A2)

    2− (1− µ0)[g(t, x0)− e(t)]

    > µ0(x0 −(A1 +A2)

    2).

    > 0. (25)

    Combining with (24) and (25), we can see thatH(µ0, u0) 6= 0, which contradicts the assumption. ThereforeH(µ, u) is a homotopic mapping and u>H(µ, u) 6= 0,

    IAENG International Journal of Applied Mathematics, 48:1, IJAM_48_1_04

    (Advance online publication: 10 February 2018)

    ______________________________________________________________________________________

  • ∀(u, µ) ∈ (∂Ω ∩KerL)× [0, 1]. Then

    deg(JQN,Ω ∩KerL, 0)= deg(H(0, u),Ω ∩KerL, 0)= deg(H(1, u),Ω ∩KerL, 0)= deg(Kx,Ω ∩KerL, 0)=

    ∑u∈K−1(0)

    sgn|K ′(u)|

    = 1 6= 0.

    Thus, the condition (a3) of Lemma 1 is also satisfied. So,by applying Lemma 1, we can conclude that the problem(1)-(2) has at least one positive T -periodic solution.

    REFERENCES[1] M. Delpino, M. Elgueta, and R. Manásevich, ”A homotopic defor-

    mation along p of a Leray-Schauder degree result and existence for(|u′|p−2u′)′ + f(t, u) = 0, u(0) = u(T ) = 0, p > 1,” Journal ofdifferential equations, vol. 80, no. 1, pp. 1–13, 1989.

    [2] P. Habets and L. Sanchez, ”Periodic solutions for some Liénard equa-tions with singularities,” Proceedings of the American MathematicalSociety, vol. 109, no. 1, pp. 1035–1044, 1990.

    [3] M. Zhang, ”Periodic solutions of Liénard equations with sigular forcesof repulsive type,” Journal of mathematical analysis and applications,vol. 203, no. 1, pp. 254–269, 1996.

    [4] Z. Wang, ” Periodic solutions of Liénard equations with a singularityand a deviating argument,” Nonlinear Analysis: Real World Applica-tions, vol. 16, no. 1, pp. 277–234, 2014.

    [5] D. Jiang, J. Chu, and M. Zhang, ”Multiplicity of positive periodicsolutions to superlinear repulsive singular equations,” Journal ofDifferential Equations, vol. 211, no. 2, pp. 282–302, 2005.

    [6] X. Li and Z. Zhang, ”Periodic solutions for second order differentialequations with a singular nonlinearity,” Nonlinear Analysis: Theory,Methods & Applications, vol. 69, no. 11, pp. 3866–3876, 2008.

    [7] R. Hakl, P. J. Torres and M. Zamora, ”Periodic solutions to singularsecond order differential equations:teh repulsive case,” NonlinearAnalysis: Theory, Methods & Applications vol. 74, no. 18, pp. 7078–7093, 2011.

    [8] Z. Wang, ”Periodic solutions of the second order differential equationswith singularities,” Nonlinear Analysis: Theory, Methods & Applica-tions, vol. 58, no. 3, pp. 319–331, 2004.

    [9] R, Gaines and J, Mawhin, ”Coincidence degree and nonlinear differ-ential equations,” Vol. 568, Springer, 2006.

    [10] S, Lu and W, Ge, ” Periodic solutions for a kind of second order dif-ferential equations with multiple with deviating arguments,” AppliedMathematics and Computation, vol. 146, no. 1, pp. 195–209, 2003.

    [11] W. B. Chen and F. C. Kong, ”Periodic solutions for prescribed meancurvature p-Laplacian equations with a singularity of repulsive typeand a time-varying delay,” Advances in Difference Equations, vol.178,no. 1, pp. 1-13, 2016.

    [12] Z. Li and W. G. Ge, ”New positive periodic solutions to singularRayleigh prescribed mean curvature equations,” Boundary Value Prob-lems, vol. 61, no. 1, pp: 1-11, 2017.

    [13] G. H. zhou and M. L. Zeng, ”Existence and multiplicity of solutionsfor p-Laplacian Equations without the AR condition,” IAENG Inter-national Journal of Applied Mathematics, vol. 47, no. 2, pp: 233-237,2017.

    [14] J. Chen, S. Xu, B. Zhang, and G. Liu, ”note on relationship betweentwo classes of integral inequalities,” IEEE Transactions on AutomaticControl, vol.62, no. 8, pp. 4044-4049, 2017.

    [15] J. Chen, S. Xu, and B. Zhang, ”Single/multiple integral inequalitieswith applications to stability analysis of time-delay systems,” IEEETransactions on Automatic Control, vol. 62, no. 8, pp. 3488-3493,2017.

    IAENG International Journal of Applied Mathematics, 48:1, IJAM_48_1_04

    (Advance online publication: 10 February 2018)

    ______________________________________________________________________________________