The quadratic formula:
$x={\frac {-b\pm {\sqrt {b^{2}-4ac}}}{2a}}$

The Pythagorean theorem:
$a^{2}+b^{2}=c^{2}$

Einstein's famous equation of mass-energy equivalence:
$E=mc^{2}$

The Navier-Stokes equation for fluid dynamics:
${\frac {\partial \mathbf {u} }{\partial t}}+(\mathbf {u} \cdot \nabla )\mathbf {u} =-{\frac {1}{\rho }}\nabla p+\nu \nabla ^{2}\mathbf {u}$

The Schrödinger equation for quantum mechanics:
$i\hbar {\frac {\partial \psi }{\partial t}}={\hat {H}}\psi$

Maxwell's equations for electromagnetism:
${\begin{aligned}\nabla \cdot \mathbf {E} &={\frac {\rho }{\epsilon _{0}}}\\\nabla \cdot \mathbf {B} &=0\\\nabla \times \mathbf {E} &=-{\frac {\partial \mathbf {B} }{\partial t}}\\\nabla \times \mathbf {B} &=\mu _{0}\mathbf {J} +\mu _{0}\epsilon _{0}{\frac {\partial \mathbf {E} }{\partial t}}\end{aligned}}$