Hyperstability of Cauchy and Jensen functional equations in 2-normed spaces

In this article, with simple and short proofs without applying fixed point theorems, some hyperstability results corresponding to the functional equations of Cauchy and Jensen are presented in 2-normed spaces. We also obtain some results on hyperstability for the general linear functional equation $f(ax+by)=Af(x)+Bf(y)+C$ f ( a x + b y ) = A f ( x ) + B f ( y ) + C .