(1)A = \pi \cdot r^2
(2)C = 2\pi r
(3)x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}
(4)\frac{\mathrm{D} \mathbf{u}}{\mathrm{D} t} =
\frac 1 \rho \nabla \cdot \boldsymbol{\sigma} + \mathbf{f}.
Applequadratic-formula
Banana cherryquadratic-formula Gooseberry
Pineapplenavier-stokesBlueberry
FAIL
EMPTY[[math]]
[[/math]]
Durian[[eref]]