\[ \nabla f = \left( \begin{array}{c} \frac{\partial f}{ \partial x_1} \\ \vdots \\ \frac{\partial f}{ \partial x_n} \end{array} \right) \]

\[ (If)(x) = \int_D k(x,t) f(t) dt \]

\[ f(x) = \frac{1}{\sigma \sqrt{2 \pi}} e^{-\frac{1}{2} \left( \frac{x-\mu}{\sigma} \right)^2} \]

\[ \int_a^b f(x) \, dx = \sum_{k=0}^n \omega_k f(\xi_k) + E_f \]

\[ G = (V,E) \]