Let r > 0 .f: (0)→R and suppose there exists an α >1 such that |f (x)| < for all x Є (0) Prove that f is differentiable at 0

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Originally Posted by mahmodmg Let r > 0 .f: (0)→R and suppose there exists an α >1 such that |f (x)| < for all x Є (0) Prove that f is differentiable at 0 What do you mean by (0)? An open neighborhood of 0? And please specifiy the condition