• Korean Journal of Mathematics
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• v.16 no.1
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• pp.103-114
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• 2008

In this paper, we investigate the superstability problem for the pexiderized cosine functional equations f(x+y) +f(x−y) = 2g(x)h(y), f(x + y) + g(x − y) = 2f(x)g(y), f(x + y) + g(x − y) = 2g(x)f(y). Consequently, we have generalized the results of stability for the cosine($d^{\prime}Alembert$) and the Wilson functional equations by J. Baker, $P.\;G{\check{a}}vruta$, R. Badora and R. Ger, and G.H. Kim.

• Honam Mathematical Journal
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• v.35 no.2
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• pp.137-146
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• 2013

Motivated essentially by their potential for applications in a wide range of mathematical and physical problems, the log-sine and log-cosine integrals have been evaluated, in the existing literature on the subject, in many different ways. The main object of this paper is to present explicit evaluations of some families of log-sine and log-cosine integrals by making use of the familiar Beta function.

• Communications of the Korean Mathematical Society
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• v.31 no.4
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• pp.791-809
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• 2016

By introducing two fractional convolutions, we obtain the convolution theorems for fractional Fourier cosine and sine transforms. Applying these convolutions, we construct two Boehmian spaces and then we extend the fractional Fourier cosine and sine transforms from these Boehmian spaces into another Boehmian space with desired properties.

• Communications of the Korean Mathematical Society
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• v.39 no.2
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• pp.407-420
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• 2024

In this paper, we investigate some geometric properties of starlikeness connected with the hyperbolic cosine functions defined in the open unit disk. In particular, for the class of such starlike hyperbolic cosine functions, we determine the lower bounds of partial sums, Briot-Bouquet differential subordination associated with Bernardi integral operator, and bounds on some third Hankel determinants containing initial coefficients.

• Proceedings of the Acoustical Society of Korea Conference
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• 1987.11a
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• pp.93-97
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• 1987

In this paper a SAW based AWZPSK modulator using the classical truncated cosine series functoins as a baseband pulse is described. A SAW AWQPSK modulator has been designed and fabricated on YZ-LINBO3 substrates. Measured responses meet the theoretical values with tolerable amounts of deviation. This SAW-based device shows good performance as a simple AWQPSK modulator.

• Kyungpook Mathematical Journal
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• v.54 no.1
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• pp.31-41
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• 2014

In this paper criterion for $L_1$-convergence of a certain cosine sums with quasi hyper-convex coefficients is obtained.

• Kyungpook Mathematical Journal
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• v.47 no.3
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• pp.323-328
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• 2007

In this paper, we extend the result of Ram [3] and also study the $L^1$-convergence of the $r^{th}$ derivative of cosine series.

• Honam Mathematical Journal
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• v.27 no.1
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• pp.43-49
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• 2005

Making use of a transparent way of convolution by tensor product of approximate identities we consider the cosine functional equation in several variables.

• Journal of applied mathematics & informatics
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• v.40 no.1_2
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• pp.233-242
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• 2022

The purpose of this paper is to find some properties and identities for (p, q)-cosine Genocchi polynomials. This polynomials which is one of Appell polynomials, have multifarious relations of (p, q)-other polynomials.

• Journal of the Chungcheong Mathematical Society
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• v.26 no.4
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• pp.769-780
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• 2013

Motivated essentially by their potential for applications in a wide range of mathematical and physical problems, the log-sine and log-cosine integrals have been evaluated, in the existing literature on the subject, in many different ways. Very recently, Choi [6] presented explicit evaluations of some families of log-sine and log-cosine integrals by making use of the familiar Beta function. In the present sequel to the investigation [6], we evaluate the log-sine and log-cosine integrals involved in more complicated integrands than those in [6], by also using the Beta function.