[tex]\it \left(\dfrac{1}{3-2i} - \dfrac{1}{3+2i} \right)^2[/tex]
Vom raționaliza numitorii, amplificând fiecare fracție cu conjugata numitorului.
[tex]\it \left(\dfrac{^{3+2i)}1}{\ \ \ 3-2i} - \dfrac{^{3- 2i)}1}{\ \ 3+2i} \right)^2 = \left(\dfrac{3+2i}{9+4} -\dfrac{3-2i}{9+4}\right)^2 =
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= \left(\dfrac{3+2i-3+2i}{13}\right)^2= \left(\dfrac{4i}{13}\right)^2 = \dfrac{-16}{169} = -\dfrac{16}{169} \in \mathbb{Q} \subset \mathbb{R}
[/tex]