An example of using \(\TeX\) formulas in HTML documents:

When \(a \ne 0\), there are two solutions to \(ax^2+bx+c=0\) and they are \[x={-b \pm \sqrt{b^2-4ac} \over 2a}.\]

Noch ein paar Beispiele:

\[\sum_{i=1}^n i^2 = ???, \quad n\in \mathbb{N};\qquad \qquad \int_0^{\frac{\pi}2} f(x)\ dx \qquad \]