# STABILITY OF A QUADRATIC TYPE FUNCTIONAL EQUATION

Lee, Eun-Hwi;Chang, Ick-Soon;Jung, Yong-Soo

• Accepted : 2007.04.23
• Published : 2007.06.25
• 40 5

#### Abstract

In this paper, we investigate some results concerning the stability of the following quadratic type functional equation: f(x + y) + f(x - y) + f(y + z) + f(y - z) + f(z + x) + f(z - x) = 4f(x) + 4f(y) + 4f(z).

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