TeX source:

\begin{array}{rclll} f\left(\dfrac{5}{2}\right) &=& \sqrt{4\cdot \left(\dfrac{5}{2}\right)^2-2\cdot \left(\dfrac{5}{2}\right)}-4 &=& \sqrt{20}-4 \quad \rightarrow \quad P_1\left( \dfrac{5}{2} \mid \sqrt{20}-4\right) \end{array}