(测试)LaTeX公式 [a^2+b^2=c^2 ][F(omega)=mathcal{F}[f(t)]=int_{-infty}^infty f(t)e^{-iwt}\,dt ][sum_{i=0}^n C_i^n =2^n ][O(Nlog N) ][O (sqrt{N^3}) ][min_{1le i le N\1le j <i}{ ext{somthing}} ][f'(x)=lim_{Delta x ightarrow 0} frac{f(x+Delta x)-f(x)}{Delta x} ]