• 충청수학회지
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• 제33권3호
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• pp.319-326
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• 2020

In this paper, we establish a general solution of the following functional equation $$mf\({\sum\limits_{k=1}^{n}}x_k\)+{\sum\limits_{t=1}^{m}}f\({\sum\limits_{k=1}^{n-i_t}}x_k-{\sum\limits_{k=n-i_t+1}^{n}}x_k\)=2{\sum\limits_{t=1}^{m}}\(f\({\sum\limits_{k=1}^{n-i_t}}x_k\)+f\({\sum\limits_{k=n-i_t+1}^{n}}x_k\)\)$$ where m, n, t, i_t ∈ ℕ such that 1 ≤ t ≤ m < n. Also, we study Hyers-Ulam-Rassias stability for the generalized quadratic functional equation with n-variables and m-combinations form in quasi-𝛽-normed spaces and then we investigate its application.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제24권3호
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• pp.171-178
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• 2017

In this paper, we define $C^*-ternary$ quadratic 3-Jordan homomorphisms associated with the quadratic mapping f(x + y) + f(x - y) = 2f(x) + 2f(y), and prove the Hyers-Ulam stability of $C^*-ternary$ quadratic 3-Jordan homomorphisms.

• 대한수학교육학회지:학교수학
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• 제14권4호
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• pp.565-577
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• 2012

본 연구에서는 중학교 3학년 학생들에게 닮은 삼각형의 대응변 사이에 성립하는 비례적 성질에 기초하여 역동적 기하환경에서 이차방정식 $x^2-ax+b^2=0$의 해를 작도할 수 있는 기회를 제공하였다. 이 예비연구를 통해 이차방정식의 해에 대한 학생들의 기하학적 직관을 촉진시키고 $a$와 $b$의 값에 따라 이차방정식의 해가 어떻게 달라지는지 시각적으로 확인해 보게 하였다. 또한, 이 과정에서 학생들이 이차방정식의 해를 구하기 위해서 어떤 전략을 사용하는지 분석하여 이차방정식 지도 방법의 새로운 가능성을 살펴보고자 하였다.

• Journal of Electrochemical Science and Technology
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• 제7권4호
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• pp.293-297
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• 2016

Here we propose a new equation by which we can estimate the baseline for measuring the peak current of the reverse curve in a cyclic voltammogram. A similar equation already exists, but it is a linear algebraic equation that over-simplifies the voltammetric curve and may cause unpredictable errors when calculating the baseline. In our study, we find a quadratic algebraic equation that acceptably reflects the complexity included in a voltammetric curve. The equation is obtained from a laborious numerical analysis of cyclic voltammetry simulations using the finite element method, and not from the closed form of the mathematical equation. This equation is utilized to provide a virtual baseline current for the reverse peak current. We compare the results obtained using the old linear and new quadratic equations with the theoretical values in terms of errors to ascertain the degree to which accuracy is improved by the new equation. Finally, the equations are applied to practical cyclic voltammograms of ferricyanide in order to confirm the improved accuracy.

• 충청수학회지
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• 제26권2호
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• pp.367-375
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• 2013

In this paper, we investigate the stability for the functional equation $$f(x+y+z)+f(x-y)+f(x-z)-f(x-y-z)-f(x+y)-f(x+z)=0$$ in non-Archimedean normed spaces.

• 호남수학학술지
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• 제39권3호
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• pp.417-430
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• 2017

In this paper, we investigate the stability of a functional equation $$2f(ax+by)+abf(x-y)+abf(y-x)-{\frac{2af((a+b)x)}{a+b}}-{\frac{bf((a+b)y)}{a+b}}-{\frac{bf(-(a+b)y)}{a+b}}=o$$ by applying the direct method in the sense of Hyers and Ulam.

• 충청수학회지
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• 제27권2호
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• pp.261-269
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• 2014

In this paper, using fixed point method, we prove the Hyers-Ulam stability of the following functional equation $$(k+1)f(x+y)+f(x+{\sigma}(y))+kf({\sigma}(x)+y)-2(k+1)f(x)-2(k+1)f(y)=0$$ with an involution ${\sigma}$ for a fixed non-zero real number k with $k{\neq}-1$.

• Korean Journal of Mathematics
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• 제20권1호
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• pp.19-31
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• 2012

In this paper, we prove the stability in random normed spaces via fixed point method for the functional equation $$2f(x+y)+f(x-y)+f(y-x)-f(2x)-f(2y)=0$$.

• Korean Journal of Mathematics
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• 제24권1호
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• pp.41-49
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• 2016

In this paper, using xed point method, we prove the Hyers-Ulam stability of the following functional equation $$\hspace{15}f+(x+y+z)+f({\sigma}(x)+y+z)+f(x+{\sigma}(y)+z)+f(x+y+{\sigma}(z))\\=4f(x)+4f(y)+4f(z)$$ with involution in paranormed spaces.

• 충청수학회지
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• 제22권4호
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• pp.757-770
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• 2009

In this paper, we prove the generalized Hyers-Ulam stability of the following additive-quadratic-cubic-quartic functional equation (0.1) f(x + 2y) + f(x - 2y) = 4f(x + y) + 4f(x - y) - 6f(x) + f(2y) + f(-2y) - 4f(y) - 4f(-y) in Banach spaces.