TeX Quellcode:

\begin{array}{rcll}f(23.709) &=& \dfrac{\sqrt{23.709+7}}{2}+77 \\&=& \dfrac{\sqrt{23.716}}{2}+77 \\&=& \dfrac{154}{2}+77 \\&=& 154 \\&\neq& 0\end{array}