Respuesta
1. $f(c)$ is defined; 2. $\lim_{x \to c} f(x)$ exists; 3. $\lim_{x \to c} f(x) = f(c)$.
Explicación
Both one-sided limits $\lim_{x \to c^-} f(x)$ and $\lim_{x \to c^+} f(x)$ must exist and equal each other as well as $f(c)$.
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What is the condition for a function $f(x)$ to be continuous at $x = c$?
Flashcard de estudio del mazo CSAT (Suneung) essentials: original practice.