• 612 differentiable ⇒ continuous
ᐥIf f is differentiable at c then f is continuous at c.ᐥ
Define a function g by
(f(x)−f(c))/(x−c) for x≠c
and f(x)ᐁx「c」 at x=c.
「g(x) Ƚx→c」
= 「(f(x)−f(c))/(x−c) Ƚx→c」
┆f is differentiable at c┆
= f(x)ᐁx「c」
So g is continuous at c.
g(x) = (f(x)−f(c))/(x−c ...
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