Just for test

[ lim_{n 	o infty} (1+frac{1}{n})^{n} = e]  $$lim_{x 	o 0} frac{sin x}{x} = 1 $$

egin{equation} label{euler} e^{pi i} + 1 = 0 end{equation}
$x=frac{{-b}pmsqrt{b^2-4ac}}{2a}$

不要在预设格式里面书写

[left{ egin{gathered}
a + b + x = 3y hfill \
ax - by = 1 hfill \
ab + xy = 2 hfill \
a + b = {(x + y)^2} hfill \
end{gathered} ight.]

$$ extrm{LogLoss} = - frac{1}{n} sum_{i=1}^n left[ y_i log(hat{y}_i) + (1 - y_i) log(1 - hat{y}_i) ight] $$

$  frac{{-b}pmsqrt{b^2-4ac}}{2a} $ 

$ p(x)=frac{1}{sqrt{2pi }}e^{-x^2} $

egin{equation} label{euler} e^{pi i} + 1 = 0 end{equation}

 [x=frac{{-b}pmsqrt{b^2-4ac}}{2a}]