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1.9 Answer

1.9

1.

$f(x)$ is continuous at $x = a$ . Then for $c - f(a) > 0$ and $\vert x - a\vert < \delta$ , then we have

$\displaystyle \vert f(x) - f(a)\vert < c - f(a)$

Thus,

$f(x) < f(a) + c - f(a) = c$

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