$ \displaystyle\lim_{x \to 5^+} \left( \frac{1}{2} \right)^{\frac{1}{x-5}} = $
Poniamo t = x - 5; se x → 5⁺ allora t → 0⁺
$ \displaystyle\lim_{t \to 0^+} \left( \frac{1}{2} \right)^{\frac{1}{t}} = \left( \frac{1}{2} \right)^ {+\infty} = 0 $
nota: 1/2 < 1.