test

$$\sum_{i=1}^ni^3={{n{n+1}}/2}^2$$ `sum_(i=1)^n i^3=((n(n+1))/2)^2` $$\int f\left(x\right)\cdot dx{\oint }_{S_1}^{S_2}f\left(x,y\right)\cdot g\left(x,y\right)\cdot d\mathbf{s}$$ $${\iiint }_{x^2-2y^2-2z^2}^{x{y}^2{z}^3}\left(\frac{x^3+\raisebox{1ex}{$4xy$}\!\left/ \!\raisebox{-1ex}{$z$}\right.}{x-yz+z^{\left(x+\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$3$}\right.\right)}}\right)dxdydz$$ $$\frac{df}{dx}\frac{df}{dx}=\frac{df}{du}\cdot \frac{du}{dx}$$ $\frac{\frac{du}{dx}}{z}$ `sum_(i=1)^n i^3=((n(n+1))/2)^2`