Sandlåda

The quadratic formula is $-b \pm \sqrt{b^2 - 4ac} \over 2a$

PQ-formeln är: $x = -{p \over 2} \pm \sqrt{({p \over 2})^2 -q}$

$i\hbar\frac{\partial\psi}{\partial t}=-\frac{\hbar^2}{2m}\nabla^2\psi + V\left( \bold r \right)\psi$