• 611 Differentiable
┄ f is continuous at c if and only if for every ε>0 there exists δ>0 such that |x−c|<δ ⇒ |f(x)−f(c)|<ε. ｢f(x) Ƚx￫c｣ = f(c) ┄ ᐥA function f:A￫ℝ is differentiable at c if and only if ｢(f(x)−f(c))/(x−c) Ƚx￫c｣ exists. The value of the limit, called the deriv ...
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