${\displaystyle {\frac {A}{B}}={\frac {D}{C}}\qquad \mathrm {} \qquad D={\frac {AC}{B}}}$

${\displaystyle a^{2}+b^{2}=c^{2}\,}$

${\displaystyle E=Pe\;V=\rho _{\text{f}}\;g\;V\;}$

${\displaystyle \pi \simeq {\frac {377}{120}}=3{.}1416\ldots }$

${\displaystyle \log _{b}(xy)=\log _{b}(x)+\log _{b}(y)\,}$

${\displaystyle f(x)=\lim _{h\to 0}{\frac {A(x+h)-A(x)}{h}}}$

${\displaystyle F=G{\frac {m_{1}m_{2}}{r^{2}}}}$

${\displaystyle {\partial ^{2}u \over \partial t^{2}}=c^{2}\Delta u,}$

${\displaystyle P(A_{i}|B)={\frac {P(B|A_{i})P(A_{i})}{P(B)}}}$

${\displaystyle \varphi _{0,t}(x)={\frac {1}{\sqrt {2\pi t\,}}}\exp \left(-{\frac {x^{2}}{2t}}\right)}$

${\displaystyle g(\xi )={\frac {1}{\sqrt {2\pi }}}\int _{-\infty }^{+\infty }f(x)e^{-i\xi \,x}dx}$

${\displaystyle {\frac {D}{Dt}}(\star )\ {\stackrel {\mathrm {def} }{=}}\ {\frac {\partial (\star )}{\partial t}}+\mathbf {v} \cdot \nabla (\star )}$

${\displaystyle {\vec {\nabla }}\cdot {\vec {E}}={\frac {\rho }{\varepsilon _{0}}}}$

${\displaystyle {\frac {dS}{dt}}\geq 0\qquad {\mbox{(1)}}}$

${\displaystyle E=mc^{2}\,}$

${\displaystyle i\hbar {\frac {\partial }{\partial t}}\Psi (\mathbf {r} ,t)={\hat {H}}\Psi (\mathbf {r} ,t)}$

${\displaystyle H=\sum _{i=0}^{n}-P_{i}\log _{2}P_{i}}$

${\displaystyle {\frac {\partial V}{\partial t}}+{\frac {1}{2}}\sigma ^{2}S^{2}{\frac {\partial ^{2}V}{\partial S^{2}}}+rS{\frac {\partial V}{\partial S}}-rV=0}$