Abstract
Some recent results have been found treating the famous Simpson’s rule in connection with the convexity property of functions and those called generalized convex. The purpose of this article is to address Newton-type integral inequalities by associating with them certain criteria of quantum calculus and the convexity of the functions of various variables. In this article, by using the concept of recently defined -derivatives and integrals, some of Newton’s type inequalities for co-ordinated convex functions are revealed. We also employ the limits of in new results, and attain some new inequalities of Newton’s type for co-ordinated convex functions through ordinary integral. Finally, we provide a thorough application of the newly obtained key outcomes, these new consequences can be useful in the integral approximation study for symmetrical functions, or with some kind of symmetry.
Keywords:
Newton’s inequality; q1q2–integral; quantum calculus; co-ordinated convexity; q1q2–derivatives MSC:
26D10; 26D15; 26B25
1. Introduction
For numerical integration and approximations of definite integrals, Simpson’s rules are well-known techniques. Thomas Simpson (1710–1761) was the founder of these known techniques. These techniques are also called Kepler’s rules because Johannes Kepler used similar techniques for numerical integration about 100 years ago. Simpson’s rule contains the three-point Newton-Cotes quadrature rule, so estimates depended on the three-step quadratic core are sometimes called Newton-type results.
- (1)
- Simpson’s quadrature formula (Simpson’s rule)
- (2)
- Simpson’s second formula or Newton–Cotes quadrature formula (Simpson’s rule).
There are numerous estimations correlated to these quadrature rules in the literature, one of them is the subsequent estimation identified as Simpson’s inequality:
Theorem 1.
Suppose that is a four times continuously differentiable mapping on and let Then, one has the inequality
In recent years, especially over the past two decades, several authors have been engaged in the study of inequalities, including the Simpson’s various function classes (Symmetric or Asymmetric). Particularly, some mathematicians have dedicated the most to the study of Simpson and Newton-type consequences for functions with several kinds of generalized convexity, given that the theory of convexity it is an appropriate way to solve a huge number of problems appearing in different areas and subareas of applied and pure mathematics. For an instance, In Reference [1], Dragomir et al. proved some new inequalities of Simpson’s type and gave some application of numerical integration using the obtained results. In Reference [2], Alomari et al. used the notion of s–convexity and proved some new inequalities of Simpson’s type with the application of numerical integration. Afterward, Sarikaya et al. observed the variants of Simpson’s type inequalities based on convexity in Reference [3]. On the other hand, Özdemir et al. used the concept of co–ordinated convexity and proved Simpson’s type inequalities for double integrals in Reference [4]. In Reference [5,6], the authors utilized the concept of harmonic and p–harmonic convexities and gave some Newton-type inequalities. Moreover, Iftikhar et al. in Reference [7] proved some new inequalities of Newton’s type for the functions whose local fractional derivatives are generalized convex.
On the other hand, quantum calculus or q–calculus is sometimes referred to as calculus without limits. In this, we gain q–analogs of mathematical items that maybe got back as . The Nalli-Ward-Al-Salam q–addition (NWA) and the Jackson-Hahn-Cigler q-addition (JHC) are two kinds of q-addition in this subject. The first one is commutative and associative, but at the same time, the second one is not. That’s why from time to time several q–analogs exist. These operators form the basis of the method which associations hypergeometric collection and q–hypergeometric collection and which gives numerous formulations of q–calculus in a usual form. The history of quantum calculus may be traced reverse to Euler who first added the q in the tracks of Newton’s infinite series. In recent decades, numerous researchers have revealed a keen hobby in investigating quantum calculus accordingly it emerges as an interdisciplinary subject. This is, of course, the quantum analysis is extremely useful in numerous fields and has vast applications in different areas of natural sciences such as computer science and particle physics and furthermore acts as a vital tool for researchers working with analytic number theory or in theoretical physics. Quantum calculus can be considered as a link between Mathematics and Physics. Several scientists who employ quantum calculus are physicists, as quantum calculus has numerous applications in quantum group theory. For some recent consequences in quantum calculus concerned readers are referred to References [8,9,10,11,12,13,14].
In recent years, because of the importance of convexity in numerous fields of applied and pure mathematics, it has been significantly investigated. The theory of convexity and inequalities are strongly connected to each other, therefore various inequalities can be established inside the literature which are proved for convex, generalized convex and differentiable convex functions of single and double variables, see References [15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32].
Inspired by these ongoing studies, we establish some new quantum analogs of Newton’s inequalities for q–differentiable co-ordinated convex functions. This is the primary motivation of this paper. The ideas and strategies of the paper may open new venues for the further research in this field.
Throughout in this paper the real numbers .
2. Preliminaries of q–Calculus and Some Inequalities
In this section we present some required definitions and related inequalities about q–calculus. For more information about q–calculus, one can refer to References [9,10,11].
Definition 1
([13]). For a continuous function the q–derivative of F at is characterized by the expression
The function F is said to be q–differentiable on if exists for all . If in (1), then , where is the familiar q-derivative of F at defined by the expression (see Reference [12]):
Definition 2
([13]). Let be a continuous function. Then, the -definite integral on is defined as
for .
We have to give the following notation which will be used many times in the next sections (see Reference [12]):
Moreover, we will need the following lemma in our main results:
Lemma 1
([33]). For the following equality holds:
On the other hand, Bermudo et al. gave the following new definition and related Hermite– Hadamard type inequalities:
Definition 3
([17]). Let be a continuous function. Then, the -definite integral on is defined as
for all .
Theorem 2
([17]). If is a convex differentiable function on and . Then, we have the q-Hermite–Hadamard inequalities
In Reference [20], Latif defined -integral and partial q-derivatives for two variables functions as follows:
Definition 4.
Suppose that is continuous function. Then, the definite -integral on is defined by
for all
Lemma 2
([18]). If the assumptions of Definition 4 holds, then
Definition 5
([20]). Let be a continuous function of two variables. Then the partial -derivatives, -derivatives and -derivatives at can be given as follows:
For more details related to q-integrals and derivatives for the functions of two variables one can see Reference [20].
On the other hand, Budak et al. gave the following definitions of , and integrals and related inequalities of Hermite–Hadamard type:
Definition 6
([34]). Suppose that is continuous function. Then the following and integrals on are defined by
and
respectively, for all
Theorem 3
([34]). Let be a coordinated convex function on . Then we have the following inequalities:
for all
Theorem 4
([34]). Let be a coordinated convex function on . Then we have the following inequalities:
for all
Theorem 5
([34]). Let be a coordinated convex function on . Then we have the following inequalities:
for all
Theorem 6.
(-Hölder’s inequality for two variables functions, [20]). Let such that Then
3. New q–Derivatives for the Functions of Two Variables
In this section, some new partial q-derivatives for functions of two variables are given.
Definition 7
([35]). Let be a continuous function of two variables. Then the partial -derivatives, -derivatives and -derivatives at can be given as follows:
4. New Identity
We deal with an identity which is necessary to attain our main estimations in this section.
Let’s start with the following useful Lemma 3:
Lemma 3.
Let be a twice partially -differentiable function on . If the partial -derivative is continuous and integrable on then the following identity holds for -integrals:
where
and
Proof.
Using Lemma 2, the definition of and it is easy to see that
From Definition 7, we have
We need to calculate the integrals in the right side of (12) in order to finish this proof. By using the definition of -integrals, we obtain that
Similarly, we get
Now from Definition 6, we obtain the following
Similarly, we get
Also, we have
and
Remark 1.
Under the given conditions of Lemma 3 with we have the following new identity:
where
and
5. Some New –Newton’s Type Inequalities
For brevity, we give some calculated integrals before giving new estimates.
and
Now we give some new quantum estimates by using the identity in Lemma 3.
Theorem 7.
Let be a twice partially -differentiable function on such that partial -derivative is continuous and integrable on . If is convex on then we have the following inequality:
where
Proof.
Taking properties of modulus in Lemma 3, we find that
Now using the convexity of , (41) becomes
Now we compute the integrals that appear in right side of inequality (42).
Thus, we have
Remark 2.
Under the given conditions of Theorem 7 with we attain the following new inequality:
Corollary 1.
Under the given conditions of Theorem 7 if we get
Theorem 8.
Let be a twice partially -differentiable function on such that the partial -derivative is continuous and integrable on . If is convex on for some and then we have the following inequality:
where
Proof.
Applying well–known Hölder’s inequality for -integrals to the integrals in right side of (41), it is found that
By applying convexity of (44) becomes
Now, if we apply the concept of Lemma 1 for to the above quantum integrals, we attain
Corollary 2.
Under the given conditions of Theorem 8 if we get
Theorem 9.
Let be a twice partially -differentiable function on such that the partial -derivative is continuous and integrable on . If is convex on for some . Then, we have following inequality
where
Proof.
Applying well-known power mean inequality for -integrals to the integrals in right side of (41), it is found that
By applying convexity of we have
By using similar operations we can compute the remaining integrals that involved in (51). Thus, the proof is finished. □
Remark 3.
Under the given conditions of Theorem 9 with we attain the following new inequality
Corollary 3.
Under the given conditions of Theorem 9 if we obtain
where
6. Applications
In this section, using our main results we can derive some applications for the following two convex functions:
Since
we need to calculate first each one of the above expressions for both convex functions, respectively.
and
Proposition 1.
Let and where Then, we get
Proof.
Using Theorem 7 with and taking where the desire result is obtained. □
Proposition 2.
Let Then, we have
Proof.
Using Theorem 7 with and choosing the above result is captured. □
Proposition 3.
Let and where Then for we get
Proof.
Using Theorem 9 with and taking where the desire result is obtained. □
Proposition 4.
Let Then for we have
Proof.
Using Theorem 9 with and choosing the above result is captured. □
All the results presented and demonstrated in this article find application both in the mathematical field, from the point of view of numerical analysis, and in that of the physical sciences and engineering. They can even be used in the area of approximation and evaluation of integrals under the work scheme used in mathematical engineering.
7. Conclusions
In this paper, using the notion of -derivatives and integrals, some of Newton’s type inequalities for co-ordinated convex functions are given. Special cases of the key results of the present paper are also discussed and new inequalities are obtained. To the best of our knowledge, these results are new in the literature. As future directions, one may find similar inequalities through different types of convexities, with emphasis on functions with some type of symmetry.
Author Contributions
All authors contributed equally in the preparation of the present work: the theorems and corollaries M.V.-C., M.A.A., A.K., I.B.S. and Z.Z., the review of the articles and books cited M.V.-C., M.A.A., A.K., I.B.S. and Z.Z.; formal analysis M.V.-C., M.A.A., A.K., I.B.S. and Z.Z.; writing–original draft preparation and writing–review and editing M.V.-C., M.A.A., A.K., I.B.S. and Z.Z. All authors have read and agreed to the published version of the manuscript.
Funding
This research was funded by Dirección de Investigación from Pontificia Universidad Católica del Ecuador as a part of the research project entitled: Some inequalities using generalized convexity.
Acknowledgments
Miguel Vivas-Cortez wants to thank to Dirección de Investigación from Pontificia Universidad Católica del Ecuador. Also, all the authors want to thank to those appointed to review this article and the editorial team of Symmetry.
Conflicts of Interest
The authors declare no conflict of interest.
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