Research Article | Open Access

# Extensions and Applications of Power-Type Aczél-Vasić-Pečarić’s Inequalities

**Academic Editor:**Peter Dabnichki

#### Abstract

In this paper, we enrich and develop power-type Aczél-Vasić-Pečarić’s inequalities. First of all, we give some new versions of theorems and corollaries about Aczél-Vasić-Pečarić’s inequalities by quoting some lemmas. Moreover, in combination with Hölder’s inequality, we give some applications of the new version of Aczél-Vasić-Pečarić’s inequality and give its proof process.

#### 1. Introduction

In 1956, Aczél [1] discovered the Aczél’s inequality.

Theorem 1. *Let n be a positive integer and let , , , be positive numbers such that ; . Then*

It is matter of common observation that Aczél’s inequality (1) is of great significance in the theory of functional equations in non-Euclidean geometry; meanwhile, many authors including Bellman [2], Hu et al.[3], Tian [4, 5], Tian and Ha [6], Tian and Sun [7], Tian and Wu [8], Tian and Wang [9], Tian and Zhou [10], Wu [11], and Wu and Debnath [12, 13] pay more attention to this inequality and its refinements.

In 1959, Popoviciu [14] gave a generalization of Aczél’s inequality, as follows.

Theorem 2. *Let , and , and let be positive numbers such that and . Then*

In 1979, Vasić and Pečarić [15] proved the following extension of inequality (2).

Theorem 3. *Let and , and let be positive integers such that . Then*

Inequality (3) is known as Aczél- Vasić-Pečarić’s inequality.

In 2005, Wu and Debnath [13] generalized inequality (3) in the following form.

Theorem 4. *Let and be positive numbers such that for , and let . Then*

Later, Wu in [11] established the Aczél-Vasić-Pečarić inequality (3).

Theorem 5. *Let and , and let , , and , . Then we have where *

Moreover, in 2014 Tian [7] also presented an improvement of the Aczél-Vasić-Pečarić inequality (3).

Theorem 6. *Let , , and , let , and let . Then where .*

Recently, the power mean has attracted of many researcher ([16–24]), and many remarkable inequalities for the power mean including Hölder-type inequalities can be found in the literature [25–30]. The purpose of the article is to establish some distinctive versions of Aczél-Vasić-Pečarić’s inequality (3) for power mean type. As consequences, several integral inequalities of the obtained results are given.

#### 2. Some Power Mean Types of Aczél-Vasić-Pečarić’s Inequality

Lemma 7 (see [13]). *Let and , and let . Then *

Like in [31], the power mean of order for positive numbers is defined by where .

Lemma 8 (see [32]). *Let be a positive sequence, . If , then the function is increasing for fixed .*

Lemma 9 (see [31]). *Let be positive numbers, and let . Then*

Putting , we get the following inequality:Let

The main conclusions of this paper are as follows.

Theorem 10. *Let , , , and , and let and . Then*

*Proof. *Simple computations lead to Since , , letCombining (15) and inequalities (10) and (8), we haveTherefore, from (15), (16), and (17), we obtain Hence, we obtain Therefore, we haveBy using (16), we immediately obtain which leads to inequality (13). The proof of Theorem 10 is accomplished.

According to Theorem 10 we can get the following corollaries.

Corollary 11. *Let and , and let . Then*

*Proof. *From inequality (21), we can get The proof of Corollary 11 is accomplished.

Corollary 12. *Let and . Then*

If we put in Corollary 11, the conclusions that we can draw from this are as follows.

Corollary 13. *Let and , and let . Then*

Let ; then from Theorem 10, we get

Corollary 14. *Let , , and let . Then*

Using the obtained inequality of inequality (26), we can get the following result of Wu [13].

Corollary 15. *Let and , and let . Then*

Theorem 16. *Let , , and , let and , and denote . Then*

*Proof. *For the hypotheses and , we have DenoteBy using inequality (8), simple computations lead toTherefore, from (30), (31), and (32), we obtain Hence ThusCombining (31) and inequality (35), we get which is equivalent to inequality (28). Successful proof of Theorem 16 is as follows.

Corollary 17. *Let and , and let . Then*

In particular, putting in Corollary 17, we obtain a new version of the Aczél-Vasić-Pečarić inequality (3).

Corollary 18. *Let and , and let . Then*

Corollary 19. *Let and , and let . Then*

If we put in Theorem 16, then we have the following corollary.

Corollary 20. *Let and , and let . Then*

Using the substitutions and in Corollary 20, we obtain the following refinement of the Aczél-Vasić-Pečarić inequality (3).

Corollary 21. *Let and , and let . Then*

If we put in Corollary 21, then we can derive inequality (3).

In particular, putting , , , , and in Corollary 21, we obtain a fresh improvement and promotion of nonequality (2).

Corollary 22. *Let , , and , and let and . Then*

Theorem 23. *Let and , and let . Then*

*Proof. *For , by inequality (28), we obtainWe get this inequality (44) by adding on both sides of inequality (45).

For the hypotheses and in Theorem 23, denote , then we have . Thus, we obtain the following corollaries.

Corollary 24. *Let , , and let . Then*

Denote , by Lemma 8, we realize that is decreasing on . Combining Theorems 16 and 23, we obtain the following corollary.

Corollary 25. *Let and , and let . If , then*

#### 3. Applications

As is well known, analytic inequalities have various important applications in many branches of mathematics [33–37]. In this section, we will get some applications for this new inequality in Section 2.

Theorem 26. *Let , , , , and . Thenwhere can be integrated on and .*

*Proof. *For all positive integers , the equidistance of the partition of is selected as Noting that , we have Therefore, there is a positive integer , like that for all and .

Moreover, for any , it follows from Corollary 13 thatWe may find that are positive Riemann integrable functions on ; we know that and are also integrable on . Letting on both sides of inequality (52), we get the desired inequality (48). The proof of Theorem 26 is achieved.

Theorem 27. *Let and , and let be positive Riemann integrable functions on such that . Then*

*Proof. *Applying Corollary 14 and along the lines of the proof Theorem 26, Theorem 27 is simply given.

Theorem 28. *Let , , , , , and . Thenwhere can be integrated on and .*

*Proof. *Combining the proof Theorem 26 and Corollary 18, it is easy to get Theorem 28.

Corollary 29. *Let , , , and . Thenwhere can be integrated on and .*

A direct result from Theorem 28 is given by us. Putting , , , , ,